I have control,
You are in luck, your revalidation should be a simple task allowing for the weather in the U of K.
If you have missed your 2 year signoff then you need to do an LPC with a PPL examiner. It should take 1-2 hours and if you are current it should not tax you unduly. The test should be enough.
Indeed I believe you can wait 5 years since your SEP rating expires and still do the same thing without having to sit any more exams, ground or otherwise.
The point to note is it must be with an examiner not an instructor. The instructor can only revalidate an unexpired SEP rating. It needs an examiner to revalidate an expired rating.
Good luck