I don't hear any Lincolnshire in Jez's (Or Robert Webb's) accent at all, and I'm from Lincolnshire O.o
To me Jez just has a standard well spoken southern accent, he could be from London, he could be from Brighton, he could be from Southampton, it's very neutral, like the English equivalent of standard Midwest American I suppose.
I also don't remember any characters having Yorkshire accents in A Clockwork Orange... I thought they were mostly cockney...
Warren Clarke had a Lancashire accent. He was in Clockwork Orange although I don't remember any northern accents in the film either. Jez doesn't have any obvious regional accent certainly not a Yorkshire one. It's nothing like that. Dobby has a Yorkshire accent. Isy Suttie is from Yorkshire.