In the UK you have no worries whatever getting seeds sent to your house. Just go ahead and order them.
I bought from Nirvana Shop and received my stuff in just over a week. They got an indoor seed category. Look for "Diffuclty" at "beginner". in the plant description. Usually at the bottom. I live in Canada and had no problem. They ship in a stealth package so that even if the customs were to open it, they would not easily find the seeds. I wouldnt recommend growing outdoor in England at this time of the year. You need a good summer weather for that. At the price you'll pay your seeds, you're better off growing indoor and sometimes taking the pots outside for some sunshine. Outdoor is dangerous : Animals, weather conditions, bugs, soil quality, nosy neighbor kids etc etc As for everything else, the information is contained in the sticky posts on top of this forum.
That's right buying, trading, possessing cannabis seeds in the UK is perfectly legal. It is in many countries. The only place that I've heard of problems is the USA. SensiSeeds simply refuses to send them there at all. July is a bit late to start cannabis outside in the UK - although there are some strains that are well adapted to growing in the climate of the British Isles and NW Europe. Hollands Hope comes to mind - being fast to grow and flower. Best of all it's highly resistant to mould attack - very important in damp climates. As for growing indoors, well your options are far wider.
There is still time to plant a few auto-flowerers outside. Ready in a couple of months. I've had good results with Diesel Ryders.
I gotta funny feeling the season has come to an end already... now for this year .. yeah ..I agree...