Glasgow Royal Concert Hall got a real flavour of Shetland on Saturday, with the stage floor even beginning to resemble a crofter's byre as a pair of comically dancing skeklers – or straw-clad medieval guizers – began to "moult" in their efforts to keep up with Fiddlers' Bid's encore and Mary Blance, the voice of Radio Shetland, offering a welcoming poem and other verses on harsh weather, fishing and the magic of fiddling in her uncompromisingly distinctive, warm island brogue.

Where the band's other special guest, King Creosote, fitted into their thinking wasn't quite so convincing, even allowing for his native East Neuk of Fife sharing fishing as a key industry. But if his brief cameos caused a certain flatness to enter the programme, Fiddlers' Bid's continued progression as they sweep along in their third decade together – a statistic that will give pause for thought – ensured there were plenty of peaks. Right from the start they showed they're intent on, and succeeding royally in, taking the music further, teasing ever more adventurous and beguiling harmonies from the ring dance tune that they brought back from a memorable festival appearance on Faro and then going on to feature harper Catriona McKay's fabulously high tensile extension of the jig-playing tradition on the Apo Fetlar Top set.

While McKay, who also plays piano, guitarist Fionan de Barra and bass guitarist Neil Harland are the absolutely bespoke rhythm section, the band's "voice2 remains its four- fiddle frontline and its now lilting, now fiery, always perfectly in synch approach to melody. Other fiddle bands are available but on this showing, they're mostly in pursuit of the Bid.

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