Transferring Youth With Provisional Contracts

Hopefully an easy question for someone, but is a player who has signed a provisional contract with a club unable to be transferred (with that club's consent) until he actually signs? I've found a total outlier newgen (PA 101, CA177 for Billericay Town in the BSS) who has provisionally agreed an £8 p/w deal with them, both my Premiership club and a Championship club have had multiple bids accepted by Billericay, he negotiates a deal at around £1,100 p/w, then three days later rejects all bids and re-affirms his provisional contract...