If your B rating has expired by 5 years or more, Twin training plus written exam at an approved school (there are plenty of them) then the flight test, send to CAA for re-issue.
Les that 5 years do a test with a M/E examiner and he signs you up.
Annually, a test with an examiner to include 1 sector and it takes about 1 hour 15min. Forget the 10 route sectors, if you have them, it saves 15 minutes on the test. Not worth bothering about.
So at the end of the day not really a lot of difference, apart from the proficiency check.