Quite simple really, go to the airfield and complete whatever training the school (RF) consider necessary; with a gap of 10 years you may need up to 10 hours training then pass a SEP class rating proficiency check and apply to CAA to reissue your SEP rating. You will need to obtain an EASA licence as your existing lifetime licence will cease to be valid on EASA aircraft after 8th April 2014. You will still be able to use it on Annex II aircraft. No written exams, test about an hour in duration.