Biggest saving, practise at home without a studio until you get all the material for your project down cold, then don't change anything when you are in the studio.
Find someone local who has done a similar CD to what you wish to sound similar to and check their recording engineer out.
Try it yourself on a computer with a decent mike, practise doing it a few times first, before you go into a studio.
Most studios will charge you an hourly rate, in Canada I can get studio time for between 50 to 100 Can$ per hour, not sure of UK prices.
Estimate an hour or so of studio time for a straight through run of a single voice a cappella recording of each song.
I know Brian Bedford is good, he is in Yorkshire though, no idea of his rates.
Good Luck, JohnB