My choice would be Glasgow

You could try the Greek Orthodox Church. They're in Kelvingrove, near to the city, 27 Dundonald Rd, Glasgow, Lanarkshire G12 9LL ‎.
http://www.stluke.org.uk/

The Greek School is based at the church. They have some links on their site:- http://www.greekschoolofglasgow.org.uk/news.html

There's plenty of Greek restaurants in Glasgow. Elia's is pretty good. (24 George Square, in the city centre, but be warned - the "city centre" goes for blocks and blocks in all directions :-) On the south side, there's Frosoulla's. In mention it because they have a good greek delicatessan just across the road.  If you check out Google Earh, - the address is 39 Sinclair Drive, Langside (off Battlefield Road), Frousoulla's looks like a construction site (just next to the pharmacy) but it is finsihed now. Accorss the road is a small place called the Golden Kebab. This is now the deli.

My advice is don't go to either of these places, especially Frosoulla's unless you are starving. Their portion sizes are amazing.

If you feel like volunteering, there's a might shelter - I think it is now in the Westend  - for homeless/destitute people. I know it's not to everyone's taste but it is a good way to meet people.
http://unitycentreglasgow.org/?page_id=474

There's also the Scottish Hellenic Scoirty. http://scottishhellenicsociety.org.uk/index.html They are based in Edinburgh but may be able to give you good links to the Glasgow greek scene.