You can either wait wait to get sunny again or pick some of the ones that looked ripest and place them on a warm windowsill. Ours are ripening very very slowly

mine are the same i have only had one so far, be patient they will ripen soon.

For outdoors tomatoes, some people suggest that you a) remove the growing tips as soon as your plants produce the third bunch of tomatoes and b) you remove all the leaves when your fruits reach the right size. Some others also suggest that you pick what ever is left green and place in a dark cupboard.
I am happy to grow only the small cherry tomatoes, They all ripen regardless of the weather and produce hundreds of fruits on each plant.

I think it is a little early to start removing leaves Costakis, and welcome to GoY!
I would agree about pinching out the growing tips though I've always allowed 4 trusses. The tomatoes, in greenhouse or outdoors, still have plenty of time to ripen...