That's bad news mate, let it marinate for a few days and then look at your options. £10k is just one estimate, it all depends on what their hourly rate is, I have some guys in Kent near me that I've used for 20 years, they only do air cooled VW's and their hourly rate goes down for the bigger jobs, especially if its on a more relaxed timescale, I'm sure they aren't the only ones. Another option is to offer it to a local 6th form or college for them to learn on, that way you only pay for parts and as long as they are overseen you should get a sound job. There's always options....