With the resources of Scotland's European Cup participants stretched to breaking point, Edinburgh Reivers coach Frank Hadden warned that the restrictions on squad sizes are threatening to undermine the tournament's credibility.

The Reivers have just named two props among their replacements for tonight's meeting with Biarritz at Gala (kick-off 7.0), while West of Scotland's Carlo di Ciacca again faces Pau with Glasgow Caledonian Reds tomorrow because they have no full-time hookers fit enough to start the game.

''It's unfortunate that in a competition of this stature we are restricted to 30-man squads,'' said Hadden. ''It must be the equivalent of Rangers having to play in the Champions League with a goalie at left back.

''Stade Francais are down to eight fit backs, three of whom are scrum-halves,'' he added to underline his point.

They have, then, had to gamble slightly with the fitness of 7ft 1in Richard Metcalfe. Having nursed an ankle injury, he came on in Biarritz only as a replacement when Nathan Hines' knee was shattered.

Metcalfe's reintroduction is the only change to the team beaten 29-18 in Biarritz, while Matthew Proudfoot, who made the trip to France but was not required is on the bench.

Biarritz have made just one change, Thomas Lievremont return-ing at No.8 in place of Jean-Philippe Versailles.

Meanwhile, Scotland A hooker Gav Scott, was deemed fit enough to travel to Pau with the Reds yesterday, but his thigh bruising is such that coach Richie Dixon does not want to risk him starting.

Glasgow Southern's Scotland under-21 prop Euan Murray has also been added to their squad.

Their team shows three changes from the side beaten 46-24 by Pau on Sunday, Ian Jardine, who takes over the captaincy, Tommy Hayes, and Shaun Longstaff replacing James McLaren, Glenn Metcalfe, and Mark McKenzie respectively.

Edinburgh Reivers (to meet Biarritz) - C Paterson; C Murray, K Utterson, G Shiel, C Joiner; D Hodge, G Burns; A Jacobsen, S Scott, B Stewart, A Lucking, R Metcalfe, D Mackinnon, G Dall, S Taylor. Replacements - P Robertson, C Smith, M Proudfoot, I Sinclair, I Fairley, K Milligan, S Lang.

Biarritz - S Bonetti; P Bernat-Salles, J Isaac, N Couttet, S Legg; F Botica, S Bonnet; D Avril, J-M Gonzalez, S Puleoto, S Nouchi, O Roumat, S Betsen, C Milheres, T Lievremont. Replacements - V Chamboulive, E Menieu, J-P Versailles, M Lievremont, N Morlaes, J Peyrelongue, B Daguerre

Glasgow Caledonian Reds (to meet Pau) - R Shepherd; J Steel, A Bulloch, I Jardine, S Longstaff; T Hayes, G Beveridge; D Hilton, C di Ciacca, G McIlwham, S Campbell, S Griffiths, J White, G Simpson, J Petrie. Replacements from - G Scott, A Watt, E Murray, D Burns, M Waite, F Stott, M McKenzie, J McLaren, G Metcalfe.

n SRU elite squad co-ordinator Roy Laidlaw has been given the added task of attempting to resurrect the nation's flagging sevens fortunes following the failure to qualify for next year's World Cup finals in Argentina.

The role of co-ordinator should fit in easily with his existing job since the plan is to use sevens as part of the development programme for promis- ing young players.