Hi Julie 
Kerry and Ofer would be perfect to chat with. I would take them up on their offer!
We also created an article on the topic of moving to Thassos where you may find helpful information: https://www.go-thassos.gr/in-focus/moving-to-thassos
Finding work on the island during the summer isn’t difficult, especially if you aren’t picky. As Kerry said, the pay is not what you’ve been used to in the UK but nor are the expenses. Here’s a 2017 post from Kerry that you may also find useful: long term rentals
In regards to your question about flights to the UK, Thessaloniki Airport (SKG) has direct flights all year round. The number of flights during the Winter is fewer and also cheaper than during the Summer. There are so many private, inexpensive airport parking lots near the airport in Thessaloniki so if you’re living here and own a car, you can drive yourself and your luggage to SKG and leave your car near the airport without paying an arm and a leg.
Kavala’s airport (KVA) mainly serves the [Kavala - Athens] route during the Winter. There are multiple flights per week so you could fly to Athens and then continue to the UK from there. This option is usually more pricey and sometimes takes longer which is why Thessaloniki is the preferred airport for most of us living on Thassos.
If you and Roger have more questions, don’t hesitate to ask here! 