Pollinating tomatoes

My tomato plants were rubbish last year. All the flower stems broke off at the knuckle and I didn't get a single tomato! A friend suggested that they hadn't pollinated so this year I'm misting daily and also using a wee paintbrush to gently brush the flowers. However, some of the flowers have started to go the same way as last years... going brown and looking to bend at the knuckle.

Any other ideas on why this is happening... if it's not non-pollination then I'm stuck. 

They're in the greenhouse... though you could say it's kind of cool in there for them at the moment! 

tomato flowers will self pollinate, they only need a gentle tap of the stem/cane/string to release the pollen into the flower, if the insects aren't doing the job. Do you open doors and windows daily?

If the flowers are falling off it's usually to do with temperature being too hot or too cold for them or lack of nutrients, such as you get when they are grown in tiny pots that can't support the growth.

It's advised to mist to help with pollination when it's hot - but I really can't see it being a problem with the temperatures we're having atm.

I've got 3 Gartenperle outside in hanging baskets. They're big strong plants now and they've been flowering for weeks, but every single flower except one has died and dropped off without producing a tomato. The single tomato I do have has not grown or changed in any way for ages. It certainly can't be pollination when they're outside, so it has to be the horrible weather that's stopping them.