There's a mobile mechanic who does blends etc at your own premises, may be worth getting a quote from him. He did mine last year - all three were done within around 2 hours or so and the aircon is back to good working order, he also includes 3 brand new blends in the price and warranties the work for a year. Cost £380 I think and that included the three new blends, which cost about £200 from a stealer. Worth enquiring anyway, and he may be able to organise the lock at the same time. His name is Jason, number 07903077948.