If you add sweetening ingredients, fruit or most other non-malt, non-hop flavourings, it's not an English bitter, but may still be a beer to your taste. Few, if any, on this site would go there, but we're here to advise, not hunt out heresy. In that spirit I'll offer a little advice.
Opening up you fermenter and at this point adding ingredients other than hops is risky in many ways. I'd leave the batch alone and stir in whatever you like at serving time.
For future reference on what to do before putting up the batch:
Fruit-added beers are generally low in bittering and not too assertive in hop flavour. Like porters.
Caramelized sugar and caramel malt add sweetness and caramel flavour. They also darken the beer. You could caramelise a sugar solution on the stove. Better, do a search for "steeping caramel malts," study and proceed.
Lactose adds sweetness alone.
Consider switching the yeast to Windsor, which leaves one sugar in the wort, maltotriose, unfermented.