good morning,
of course the UK CAA will accept the renewal. Make sure you ask for a copy of the medical report (enough for the Irish IAA), maybe take also a copy of every part of the exam to be on the safe side. You then get the medical issued immediately. You should inform your CAA by fax or email, attaching the report. I stand to be corrected if the UK CAA does it differently again...
Depending where in Italy you are, you may want to get a low cost flight to somewhere else (BTL, PRG), where you can simply show up, get the medical, get a couple of 50 cent beers (preferably after!) and pay 55 Euro for the renewal...
cheers, IP