Can I make a suggestion if you see this lady regularly?
Buy her something small as a thank you. Nothing excessive, maybe a bottle of something (if she drinks) or something like that. So many people of this kind will give of themselves and receive not a lot in return. It's something I've been trying to work on lately, and people really do seem to appreciate it, but it shows them just how much of a difference what they did made.
I had a not dissimilar instance this weekend with our lodger, who happily looks after the cat whilst we are away, and has since had the chickens added to the menagerie. I finally remembered to get him something as a thank you, and said "that's not necessary, I live here anyway", to which I replied, "if you hadn't, I simply wouldn't have been able to go away and have a fantastic weekend, and I want to pass some appreciation of how good it was on" (plus it was wine, so he accepted.)
I think I've wandered a little here, but you get the idea

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