Ooh, if I were you I'd roast loads of veg and mix it with some couscous made with stock, or some brown rice. That'd be free! Make sure you have loads of veg, and the carbs should be enough to see you through! I'd also take some satsumas, but that's because I love them! But some crudités to snack on would be a good idea. Carrots, cucumber, celery, peppers, all sliced up and put in some Tupperware or even a sandwich bag so you can just dip in if you're hungry.
I live in Manchester and there are loads of places in town to get a jacket potato with beans. There's a stand on the main high street called "what a potato", in the Arndale food court theres a potato place but my favourite is in the food bit of the Arndale Market. There's a lady who does jacket pots with beans and she does you these nice big side salads so perfect for Extra Easy! You can also buy loads of dead cheap fruit in the Arndale Market, I once got a punnet of strawbs for a pound!
If you're going for a lunch in the northern quarter, I've been to Oklahoma cafe a couple of times. It's a bit hippyish and the staff are rude but it does the most amazing options for slimming world- baked sweet potatoes and the best toppings- feta, beetroot, mint and apple is to die for!
If out for the day I take a tupperware with a pasta or cous cous salad in it - more than I think I need just in case the unexpected happens. Plus an apple and grapes. Maybe a couple of Alpen lights for a Hex.
Depends what plan you're on as well, but sushi is a good bet if you are out and need to grab something.
tuna pasta salad
slices of cold lean meats
loaded potato skins
low syns crisps like french fries, quavers or walkers lights
laughing cow cheese & ryvita minis
low syn cereal bars or ones which are a heb choice