I use a small banana addition in a lot of wheat beers these days - I use the WB-06 dried yeast which is a typical German clovey style yeast without the banana esters of the Bavarian style. Addition of 1 or 2 bananas just before flame out, gives it a lovely lift

bananabread bitter is in the fermenter as we speak.
Edit; I hate the banana essence, doesn't smell like real bananas at all to me & has a synthetic taste, though maybe you have a better product in the UK. Generally I freeze the pulp & defrost before adding to primary as ferment finishes. For the BB Bitter, I've tried boiling the fresh bananas & just adding the strained liquid. The boiled bananas have a very different aroma (more like banana cake) so hoping this will go better in the bitter - time will tell.
cheers Ross