Most likely if there is a big city with a tournament, then there shall be players there.
Even smaller towns have an active Pokemon league in certain areas near me such as:
Crawley and Aldershot. The bigger cities such as Southampton and London defiantly have active leagues/premier events so I would not be surprised if Manchester has an active Pokemon TCG community.
In terms of learning the game there are many resources available. If you're looking to watch good tournament play, than "The top cut" is a good youtube channel showing various deck profiles and battles.
They are a group of american players who are considered Worlds competitors so you can't really get better than that.
The official Pokemon trading card game website will have resources to show you have to play the game such as tutorials etc.
If you're looking for buying packs/booster packs than Boundaries crossed is one of the best sets to buy due to having good overall EX Pokemon and decent Ace-specs.
The new set plasma storm has good Ace Specs but the EXs are fairly limited. The plasma storm set is mainly the new supporters/trainer items in the set which make the set worthwhile. Also if you plan to construct the new poison style deck with Crobat then it could be a worthwhile investment. Lugia EX could also be a viable attacker but we are yet to see what impact plasma storm will have on the game.
The Pokemon tins with Darkrai EX, Mewtwo EX and Rayquaza EX are a best place to start when it comes to buying packs as you get an EX which is worth half of the RRP of the tin alone ! They are great value for money and all of the EXs are seeing tournament play.
Mewtwo EX is a very universal attacker and it's seen in majority of decks.
Most tournaments are going on this weekend such as the ECC (European challenge cup) which is classed/considered as a "European Worlds" but plasma storm is not legal for that event and I have a city championship on Sunday which will be technically the first event with legal plasma storm cards. I have no new cards, so I shall have to make do since it's too short notice to get most of the new supporter/item cards in time.
The current top tier decks are:
Blastoise/Keldeo EX/Mewtwo EX
Mewtwo EX /Ho-oh EX with various attackers
Darkrai EX Variants such as Hammer time, Darkrai EX/Mewtwo EX, Darkrai EX with various fighting attackers such as Terrakion/Landorus EX
But it may change once plasma storm has a few months of legality and settles into the current format.