Film was certainly made in Harrow, I'd guess up to 7-8 years ago. Master rolls were shipped about 150 miles up the M1 Motorway to be cut and packed at the factory at Annesley, near Nottingham (Robin Hood country ). There was a large modern Kodak finished factory there (all now gone), and I have several Ektachome boxes "Finished and packed at Annesley, Nottingham, England". It was quite usual to spot several Kodak trucks whenever travelling on the motorway.
(I'm wondering if, even if film coating resumed at Harrow, there is any finishing equipment left there, as the Nottingham finishing plant was in operation something like 15-20 years...not got the dates to hand, but I know they're on the web somewhere).
If not, I'm sure Simon's crew at Ilford Photo in Mobberly would be happy to finish Kodak film. I'm sure they still have the equipment, since they do it in B&W and finishing color I can't imagine would be too terribly different from B&W.
Shoot more film.
There are eight ways to put a slide into a projector tray. Seven of them are wrong.