We are in West Yorkshire so weather is not as hot, usually, than the South of England.
I live in West Yorkshire too, but all is not lost providing you grow the right variety and place them in the sunniest spot in your garden / Allotment.
Both my son and daughter grow the plants I give them every year outdoors and they generally get a decent crop.
I set them up with a couple of plants apiece but I am quite selective in what varieties I give them for example I only give them types recommended for outdoor growing or they are miniature variety.e.g a variety similar to Gardeners Delight
Strangely enough when I give them an outdoor variety they find that these do not perform as well as the miniature varieties.
I have thought about this and I put it down to the ripening process I.e. The small fruited varieties ripen quicker than the larger salad types .
This is also backed up by the commercial people producing varieties that will grow in a wall / hanging basket as invariably these are small fruited varieties.
These have another thing that is common with the plants I give my son and daughter......they are bred to be grown in containers so I plant these in large pots, usually a supermarket flower bucket.
Being potted they can be sited in the best spot possible as opposed to in a bed where this might not be the best spot you have.
Another factor is aftercare this is usually more demanding than plants grown in a bed / border as they do not have the same root run so watering and feeding is more critical, add to that they are growing outdoors.
In terms of height I put a four foot cane in the pot with the instruction to take out the growing tip when it reaches the top of the cane, plus do not remove all the side shoots as you would do when growing as a cordon, leave a couple to grow on and this effectively gives you three dwarf plants with a couple of trusses on each. You actually end up with a bushy plant irrespective if you have grown a determinate or indeterminate.
I hope you find this idea useful...Tg