A cheap tent, while easy on the bank balance is not the most ideal lodgings during your typical British summer.
A cheap tent will be cold during the night due to its single layer of shower proof fabric. A more expensive tent will have 2 layers of fabric which will create a double glazing effect keeping the warmth in the tent and the cold outside the tent. A cheap tent will be cold at night.
On an cheap tent that single layer of shower proof fabric will do exactly what it says on the tin - a short light shower of rain will roll right off it but a long heavy down poor will soak right through and cause uncomfortable drips to fall on your head, neck and back making you cold wet and uncomfortable.
A cheap tent will be small. Small tents have small doors. Small doors can be tricky to get in and out of, especially and 4.30am when you are still a bit drunk and desperate to got to the loo.
Never buy the cheapest tent.