Veggie and never liked real bacon, happy to eat veggie bacon though.
My suggestions:
Along similar lines I feel as a scot you can't beat what we call a hot roll. Basically a crusty roll with a gorgeously doughy inside, well buttered and then filled with whatever fry up items you choose. My personal favourite is a perfectly fried egg (white cooked but NOT burnt and the yolk still runny) and a tattie scone - actually make that 2 tattie scones, triple carbing! Others might enjoy 1 2 or 3 of the following: bacon (that'll appeal to you op), black pudding, lorne sausage, white pudding, scrambled eggs, fried tomato, fried mushrooms
My ex fell in love with this particular aspect of Scots "cuisine" which was totally new to his quite conservative food tastes. He was a fan of triple meat - bacon, lorne sausage and black pud.
Another favourite:
Bagel toasted, one side cream cheese, one side "buttered" with pesto sauce, chopped sundried tomatoes
A twist on an American idea:
Peanut butter and lemon curd sandwich - trust me! The citrus cuts perfectly with the texture and sweetness of the peanut butter
Christmas special:
White bread thickly sliced, leftover Xmas dinner items: roast potatoes sliced snd fried, sage and onion stuffing balls also sliced and fried, "butter" the bread with cranberry sauce, fill with the potatoes and stuffing - yum!
@sequinednostrils try marmite and jam - honestly! If you like a sweet salty combo this is perfect
See also cheddar and jam, Red Leicester and jam, or marmalade...
I've just learned an old school friend of mine who I knew went into catering, has 3 "caffs" now - "cafe" would be too posh! One is a traditional greasy spoon, one is a family lunch type place and one ONLY does sandwiches and "on toast" and this includes deliveries. You can order marmite on toast as a takeaway! The menu is very inventive though going from traditional favourites up to and including a lobster and crab toasted baguette! I hear it's doing a roaring trade even in lockdown.