And what an exceptional film as Benedict Cucumberpatch was...... Alan Turing! There were a few slight boobs though, the first being the 1951 use of an Eddystone 770R - which wasn't actually on sale until 1953. Then there was the Anglepoise lamp in Alan's Styal flat - correct colour, correct two stage base BUT with an incorrect non-rolled wired shade rim not first seen until 1958 post austerity and all that. Sticking with the lighting theme, the Dugdills patent lamp situated to AT's left during the bear joke scene had a fetching but decidedly not period white plastic 1970's bayonet light fitting. The last thing to be spotted was when Alan & Joan took a train trip to see Mr MI6, they were sitting in an example of outwardly LMS coaching stock but with the corridor compartment unfortunately fitted with 1970's British Rail blue moquette seating.
But other than the above four very minor points this was a most enjoyable film.