Hang on a moment,
Bowiefreak, who are you calling 'old'? With that screen name, I can only assume that you were around when ground control was calling Major Tom. In which case, you're probably as old as me ;-)
Matt:
If you do decide that you'll have to travel via Athens, the maps here
http://www.aia.gr/pages.asp?pageid=992&langid= 2
show that the only operator to Kefalonia is Olympic Airways. They also show that Olympic operate from both Heathrow and Manchester to Athens. (The only other flights from the UK are with BA from Heathrow or with easyJet from Gatwick & Luton).
Olympic can fly you from Heathrow to Kefalonia, on Thursday 20 December for �105 + taxes and charges. (The connection time at Athens is 2 hours 45 minutes). However,you get stuck in Athens for a day on the return journey. (Land at 0800 one day. Depart at 0700 the following day). Fares range from �69 to �229 (+ T&C), depending upon the date of travel
http://www.olympicairlines.com/
It might be best to fly out with Olympic but to combine the Olympic service, ex Kefalonia, with a BA or easyJet flight from Athens for the return journey:
http://www.britishairways.com/travel/home/publ ic/en_gb
http://www.easyjet.com/en/book/index.asp
Chris