you said 2-man but you didn't say do you need bike portable, backpack, or car portable if you need bike or backpack portable weight becomes an issue as does pack size consequently cost. vango DofE stuff is good but its heavy as is its force 10 stuff. your son is in the scouts not ventures? So 4/5 season is unlikely to be needed.
The average lifespan of a modern polyester tent is 4-weeks summer sun for 5 years so don't be tempted to buy any of the ex display stuff that is around at the moment you need a minimum 3000hh for british weather 1500hh is rated waterproof by the british army but campers recommend 3000hh.
Even more than bikes production of tents is centred in china in fact 90% are made at the same factory complex so what you are paying for is design and quality control. Avoid
halfords and argos you can get decent tents from them but the QC at the factory is not so good and quality is very variable likewise gelert their top of the range is ok but design is not as good as some. If you are going for a pop up tent quetcha by decathlon are highly rated however pop ups are light but not very portable because of their pack shape. Always avoid
Ebay own brand eg rage they are the bso of the tent world usually low hh and thin poles that snap.
Footprint groundsheets are a good idea to protect the tent but obviously add to weight and are pricey typically 20-45 pound depending on models cheaper to buy a tarpaulin from b&q and cut it to size.
vango do various ranges so be careful, their budget ranges are as bad as anybody's. outwell have a good name in the camping world but their 2 man stuff is not highly rated.
north face is highly rated but pricey
vaude or wild country which is its budget subsidiary are good, the coleman 2man tents are highly rated as are aztec.
In general the more portable the tent the pricier it becomes. As has been mentioned if portability is not essential you should be looking at 3 man tents as 2 person tents are very snug hope this helps