NO your license is valid for 5 years.
Your SPA-MEP-IR is valid for one year and maybe revalidated in an FNPT2 or the aircraft.
Your MEP class rating is valid for one and has to be renewed via flight test in the aircraft but maybe combined with the SPA-MEP-IR.
The 12 hours in the aircraft relates to the SEP class rating which is valid for 2 years and in the final year you must have done 12 hours in a SEP 6 of which must be as PIC and 1 hour dual with an instructor in which case you can renew by experence or if you don't have that many hours you can renew with a skills test.
It can be done by any other JAA authorised examiner but your will have to supply a copy of the examiners approval and maybe even more hoops depending what mood the person who opens the envelope in the caa with your paper work.