Transferring money to seller

Hi, first of all i apologise for whats probably a basic question. Im a first time buyer, approaching exchange of contracts in about 3 weeks time.

M y question is whats the best way to get my money to my solicitor to pay the depost, I have 12k in an ISA and 7k in another online savings account with the same back. My other half is also contributing another 3k from an ISA with a different bank.

We have already been quoted £25 CHAPS fee on our list of fees from the mortgage broker, will I have to pay an additional CHAPS fee for each of the 3 payments I will be making to get the deposit over, or is there a better wya to do it, perhaps BACS?

Thanks - Will