I have a very rough budget with meal plans for the week
That is good. But I also think with your financial position it's important to really enjoy your retirement - make the most of every part of it.
If this week you fancy salmon and scallops - go for it! There are probably bigger things you could cut down on than choosing bargain chicken nuggets to stay within your food budget.
I have a financial advisor, who manages my ISA and pension, and they have a giant chart with my income / expenditure (I had to give this to them). It plots possible capital growth, factors in when I'll get my state pension. It did have potential inheritance but care home fees have swallowed that so we've taken it out.
The reality for me is that there will be be 18 months when I'm eating into my capital. Then state pension kicks in and things are back on a positive keel. Also FA predictions show that, in general, level of spending decreases a lot after age 80. So it becomes quite difficult to spend the same amount of money as you did 15 years earlier when you were 65.
Utlimately, the big asset is your property. Is it somewhere suitable for you to live forever (ground floor bedroom / accessable shower / manageable garden / level walk to shops etc). Start thinking and planning for that now.