Yay for OH being paid, enjoy the fish and chips if you have 'em!
Picnic stuff is high in pp indeed - pastry, argh!
WW snacky bits are always good if they're on offer, otherwise salad with chicken/bacon or potato/pasta salad? sugar free jelly is always a nice treat (zero cal too!), ryvita/crackers with low-fat cheese spread/cottage cheese, fat-free yoghurt with fruit? maybe add some cereal to it too, babybel lights if they're on offer, multipack crisps (pom bears/skips/quavers are all only 2pp/bag), bagel/pitta bread with a yummy filling, fruit/dried fruit, veg sticks (celery/carrots/cucumber) with a dip/low-fat houmous, chicken is always good/ready cooked chicken/chicken legs if you remove the skin, fruit loaf/malt loaf with margarine or jam, a small scone is only 4pp as a treat
, or you could make a pastryless quiche which are usually extremely filling, I use quark which isn't too expensive and is a fat-free soft cheese but has a sort of yoghurt-like consistency, add 3 eggs per 250g quark and then whatever filling (any meats/veg/cheese) - any combination you fancy, and it's very, very low in pp! Otherwise, a hard boiled egg isn't a bad option for the picnic, bagels/pitta breads/wrap provide a nice alternative to sandwiches, boots do a 'shapers' range which is cheaper than WW food and you could probably pick up a nice treat (choc bar etc) without paying as much as you would for WW stuff in a supermarket