a) if the U8's at Aberystwyth was not FIDE rated then the Welsh rules should apply and not ECF rules or process, unless otherwise stated on the tournament program.
b)
Depending on what the arbiter said this may have been correct at Canterbury but it's always been possible to appeal against a decision by an arbiter not to allow a 10.2 claim to be put, for example if a player leaves the claim until the last few seconds.Alex McFarlane wrote:In the other case an arbiter made a wrong 10.2 decision (draw in the last two minutes) by rejecting a valid claim. At that time the Laws of Chess prevented an appeal being made for such a decision.