If the EU decides that the sale of the stadium to Wasps was unlawful state aid then SISU would, of course, launch further legal proceedings against the council and possibly Wasps demanding compensation. The longer they are playing away from Ricoh paying (presumably) high rent the more compensation they will demand. Interestingly, and worryingly for CCFC fans, if SISU wants to maximise the compensation then it wouldn't be bad for SISU if CCFC went bankrupt in the next few years, before the case is decided. That has the added bonus that SISU would no longer need to finance the football team's day to day business in order to make a profit from the asset.
Alternatively they could sell the club and, should the EU decide in their favour, claim they were forced to sell the club for less than it should be worth, and claim compensation on those grounds.
Fun fun fun!