Need beer for a recipe - which beer should I buy?

[MrsFogi]

I have never bought beer so have no idea if some brands are better than others to use in cooking. It is just to make a tasty Welsh Rarebit.

a bottle of bitter.
i'm a suffolk girl so Adnams is the best.
London Pride works well.
Even lager.
If it tastes a bit too bitter a teaspoon of sugar will fix it.