No, golf stuff generally are the same price in london, probably a little more expensive if you go to any golf shop.
You could however buy them online from certain sites which is cheaper but you have to be careful of fakes i guess.
Depending on what you want, check out americagolf which has quite large stores at some driving ranges . Two are particularly central here, one is at northwick park on the metropolitan line which is about 4 or 5 stops from Baker Street.
The other would be at New Malden which is around half an hour from London Waterloo.
If you cant go out that far, there is a nevada bobs at liverpool street station which is big and has a bay to allow you to try the clubs. its pretty similar to Isetan at shaw.
Also , Lillywhites at piccadily circus has some golf equipment , the balls and tees are especially cheap and it does carry a wide range of beginner equipment .
pm me if you need more info!