How many tomato plants?

[Sambucus]

This is my first year with a greenhouse and I was looking forward to lots of home grown tomatoes - maybe even too many. Despite having 6 plants (5 cherry variety and 1 moneymaker type) I am still only harvesting around 5 cherry tomatoes per day. Did I underestimate how many plants I needed? I feel underwhelmed by my harvest!

pollination has been patchy for me this year, not just on tomatoes but on everything in the greenhouse and even things like courgettes outside - I think extreme heat impacts on pollen and also its been strange timing on flowering/pollinating insects this year - the plants are in the same place at the same time as they were last year and previous years but, eg, one of the chillies has been cropping heavily since May and the other two have only got a few fruit and they're only starting to ripen now.

Next year I will perhaps try and hand pollinate some if we have similar weather, but some years things don't work, other years you get massive crops... its the way it goes!