Hi Ann and Liz, also waving hi from Surrey!
Great comments here from Elizabeth and I can personally vouch for her approach to feeding as I've seen her kitties many times and they are always in beautiful condition!
I too feed Nature's Menu (and Country Hunter, which is part of the NM range). There's a "senior" variety of the standard NM which I think includes fish, so depending on your views on that, it could be worth considering as part of a mixed diet as it does vary things a bit.
It's worth looking at the protein content of some foods as even the better-quality pouches aren't always too high in that respect, and I think it's important to keep protein levels up as our kitties age. What I sometimes do is add to a serving of NM a little shredded chicken in broth (Encore, Applaws, Almo Nature) which are not "complete" foods but increase the protein content of the meal and have the added benefit of keeping my kitty more hydrated than she would otherwise be (she doesn't drink water).
I shop at Fetch which is very reliable and super-quick.
Good luck, let us know how you get on