Adam & Co, the private bank founded 30 years ago in Edinburgh, is celebrating that anniversary with a relaunch led by managing director Graham Storrie, who says the bank is about to power ahead after a bumpy ride.

Adam's move from its original Charlotte Square townhouse to a customised new building in St Andrew Square, with faux Georgian reception rooms, symbolises the move to more modern banking for its comfortable clients. They must now have at least £250,000 of investable assets to get Adam's formerly "free" service or pay a £40 a month tariff.

Mr Storrie started his banking career from school with the RBS in 1977 before heading off to Abbey National and Standard Life, rejoining RBS in 1994. He ran the bank's insurance joint ventures until 2009, when RBS handed its last one back to Aviva.

"It seemed to be the perfect time to look for a new opportunity," says the banker, who had just turned 50. "I threw my hat in the ring when they were close to appointing an external candidate, and started in January 2011. What attracted me was this was not going to be straightforward, but the group and the wealth division were very keen to invest in this business."

Rescued 20 years ago by Royal Bank of Scotland after the independent bank foundered on a £21 million foreign exchange loss, the bank flourished as a highly autonomous corner of RBS under chief executive then chairman Ray Entwistle, growing pre-tax profits steadily from £2m to £19m.

Then came the crash, the folding of Adam into the RBS wealth division with 300-year-old Coutts, and a string of departures and defections, followed by the shedding of 130 jobs at the bank last year.

Pivotal was the installation in 2010 of RBS group executives to run the bank, and the stripping away of the 11-strong board chaired by Mr Entwistle, who described it as "a change in strategy". That gave fresh ammunition to rivals painting Adam as an emasculated outlet of RBS, but it was accompanied by the investment programme which has given Mr Storrie a new story to tell.

The Adam board is now back up to nine, with three non-executives, the Coutts chief executive Michael Morley, and five executives including head of banking Kerry Falconer, the former aide to Fred Goodwin whose appointment as interim managing director in 2010 was said at the time to have helped speed some departing staff on their way. The bank's £1.9 billion of deposits are up on the £1.7bn of 2008, it has a £750m loan book, and 14 portfolio managers looking after £1.3bn of client assets. The chief executive admits: "It has been a pretty tough five years."

But he says clients can take comfort from a "really strong investment performance" from its core fund over one, three and five years.

Much of that was achieved under former investment chief Harry Morgan, who left a year ago, but one fund managed by Mark Ivory and Anna Croze did win an industry award this month. Mr Storrie insists: "This is a business going back on the front foot and attracting new people."

The big change is the modernising of the bank's IT platform, enabling it to "segment" its client base rather than offering "the same service whether you had fifty grand or fifty million", Mr Storrie says. The new £40 fee for lower rollers did drive some clients away, he says, but "less than we expected", with some leaving only to come back.

He reveals that the bank's "sweet spot" is clients worth at least £750,000, while the restructuring has created "a more sensible number of clients per banker" and the use of wealth division hubs. "What we don't have is call centres, clients are always able to continue speaking to our bankers, but things like payments would be done through a centre of excellence in London."

He adds: "We don't have wrapped packaged products, it is bespoke discretionary fund management delivered to each client's needs."

Now Adam faces a potential new challenge from Mr Entwistle's own Scoban venture – a private bank founded on old-fashioned banking values with no products to sell, harking back to the original vision of Adam. The new bank is poised to secure a licence and hopes to open for business in a year.

Mr Storrie says: "I welcome competition – if you lose clients, you lose them because you deserve to. If Scoban gets off the ground, bring it on." But he suggests the new bank's pure banking proposition may be "narrow" compared with Adam's. "You need these traditional values with a modern twist, you need apps, you need to be able to give advice and talk about investment."

Adam has branches in Manchester and London, as well as Glasgow and Aberdeen, and does 40% of its business south of the Border alongside Coutts. "There is plenty of room for two brands," Mr Storrie says, contrasting high-profile Coutts with Adam's "understated and discreet" image. But he stresses the Scottish dimension, with looking after the private interests of RBS business customers, and says there have been "misconceptions" about the bank's autonomy.

"I am left to run the business, and one thing I have done is to bring in two new non-executives ... I also think it is good to have a relationship with Coutts, which does wealth management in 60 countries, and the investment in new offices is a benefit of being part of that big group."

This month will see the launch of a new range of cash management products, Mr Storrie says, while the IT overhaul will revitalise the business and sweep away what he admits is an "antiquated offering". Full transactional online banking will be available via pc or iPad, to be followed by an Adam smartphone app.

"You could argue this only brings us up to date with the high street banks... we are now at the table and have a very good proposition," he says.

The move from Charlotte to St Andrew squares has cut operating costs in half, to £600,000, Mr Storrie says. Latest numbers are under wraps until July, but Adam is likely to report a rise in profit and a fall in bad debts, which ballooned last year from £400,000 to over £9m.