hey mate...Galloway is meant to be pretty good as they always have space to fit walk ins and have several people here that have used them, but otherwise try CGC Engineering if they will take your job...
CGC are meant to be the best in the business from what I've been told by a few engine builders but don't take on new customers as they're too busy to cater for the public, you can try your luck though.
My head work on my recent build was completed by CGC and I'm a happy camper.
Try both, see who can fit you in sooner
