Best advice i could give you Richard is to either DONT GO or find a local that is can remember catching a fish there.
As you might of guessed not a water i'll be going back to.
At a guess i'd say it would be a hard water for Pike as there are alot of very small fish (i had 11 fish for 6oz)
To give it any chance i'd recommend a good fish finder on a boat as it is a vast expanse of water to locate the small density of fish, similar to Loch Lomand except Bala has LESS fish.