Hi Scott
I use www.voltrexfx.com
Voltrex Foreign Exchange (VFX)
5 St Helens Place
Bishopsgate
London
The charge an flat admin fee of £5 for each transaction whether it be 500 euros or 2000 euros. Generally it is around 1 base point lower than the commercial rate identified on the BBC. One you have completed your original registration. It just a phone call for each occasion you want to transfer money to your account in Spain. Never had any issues with them.