Re: Executors expenses !
Been there, done that. The key for me was the idea of "reasonable". I can't, for example, think of a reasonable non-zero amount that you can claim for receiving mail.
The first thing I did was to buy a good hard-cover notebook in which I recorded everything I did, particularly including every financial transaction, even the smallest -- and the first entry was the cost of the notebook.
Postage is easy -- the cost of stamps and fees like those for registering some letters. I made what I thought were reasonable estimates for stationery and telephone costs, and told the beneficiaries in order to be sure that they agreed I was being reasonable. Motoring I charged at the rate that I was allowed by my employer. Everything else (including a few meals taken away from home) was specific outlay, and I kept all the receipts.
Had I lost any income -- say taking time off work to deal with estate matters -- I would have claimed that, but it didn't arise.
It helped greatly that the beneficiaries all trusted me.