Not sure how many of us are flying aircraft that has a FIRST CofA issued after 1st July last year?
Bose-x, it makes no practical difference.
If first CofA was issued after 1st July 2008, the aircraft must have an ELT-AF, ELT-AP or ELT-AD.
If first CofA was issued before 1st July 2008, the aircraft must have any of the above or a manually-activated ELT-S.
But, as I've noted before, ELT-S is an ICAO and EASA defined term which expressly doesn't embrace the PLBs that most of us use. The latter don't meet the ELT-S requirements for crash-worthiness, 121.5MHz homer power output or transmission of the aircraft's ICAO 24-bit address.
I've listed examples of approved ELT-S beacons in post #8 above. I believe all of them retail for more than £2,000, whereas the entirely adequate GPS-enabled PLBs we use are available typically for £300-£500.