i think from the players i mentioned before
Mcdonald, Flanagan, Brocklebank, Maxwell, Huby possibly Murray could all go straight into the U21's without any problems. Seeds and George would need to gain some strength but both very good prospects
To be honest i dont rate Olstrum that much he is a decent player who looks really good because there arent that many great players in he's league
Players like Michael Ramsden Gareth Herbert Tony Burns Stevie McMillan Mark Pearson are all worth a look at