Nicola, Nicola... you've fallen into that mindset that associates lettuce with salad. I think its a British thing, padding out every bowl of salad with masses of tasteless, force grown, irradiated iceberg lettuce.
You have to stop and think... what is a salad? In my opinion, it is any cold dish that contains mainly vegetables, with or without some cold or warm meat, that is bound with a dressing of some description. Using that a baseline the choice/combination of ingredients are endless - cold cooked root veg, thinly sliced raw vegetables, beans, pulses etc etc.
A few that come immediately to mind:
Any greens (kale, shredded brussel sprouts, savoy cabbage) with walnuts or pine nuts and a vinaigrette or creamy dressing.
Selection of cooked beans - kidney, pinto, cannellini, blacked eyed with a nice herby dressing
Thinly sliced fennel with cucumber and a spicy dressing
Shredded chicken, green beans and coriander with a coconut based dressing
Beetroot and feta with a lemon dressing
Rather than using the boring old iceberg type lettuce to add "green" to a salad, experiment with other leafs such as watercress, spinach or chicory. For a splash of colour, there is radicchio, cavolo nero etc.
I rarely cook in TR so not sure whats available in the markets, but by doing a bit of lateral thinking I'm sure you'll come up with stuff other than lettuce to make your salad.
JF