Firstly, yes get it serviced, and have someone competent give it the once over for peace of mind (service cost approx. £300). I, rightly or wrongly, always suspect that raffle/lottery/prize cars are thrashed to within an inch of their lives before the giveaway.
No idea how to obtain the service history, as aside from the service book, the onerous GDPR tends to preclude the passing on of documents or info from the previous owner(s).
NuT to Essex will be a bit of a journey (although there are some that travel further) but my personal recommendation is FJRS Unit 2 Harrison Dr, Braintree CM7 1DE. https://www.fjrs.co.uk/ Think of it perhaps as an annual pilgrimage interspersed with a good long drive.
FJRS are well versed in all things fast Ford, and have gained a well earned reputation for quality workmanship & professionalism with a personal touch.