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@ClubMan said the Moneymakeover section is likely where you can get some good advice. I'm not going to give any heavy financial advice, but:-
1. Apply immediately for the Old Age Contributory Pension - Not means tested
2. If OACP is not applicable apply for the Old Age Pension - Means tested
3. She may be entitled to a Living Alone Allowance with either pension
4. The Free Travel Scheme is not to be sniffed at and while you're at it let her apply for free travel in Northern Ireland too. These open up possibilities for a happier retirement
5. At 69 likely she wants ready money available to her so no point in looking for investment opportunities where money can be tied up
6. She is still working but wants to retire, do everything possible for her to have her wish (Even she can be done without)
7. Ensure she does nothing like (my opinion only) looking at after life loans.
8. Her circumstances might dictate that three months in sunnier climes during winter/spring where she can live more cheaply is a positive option.
9. Retirement is where family/extended-family contact matters most
10. She may feel like downsizing on the car front
11. If she joins a choir, ICA, Bridge Club, Cookery Course, (or whatever) she gets some free focus from others. [I don't know your MIL and perhaps she wants to join a motorcycle club?]
12. Don't forget to have her apply for a free television licence (everything matters!)
13. Get Netflix if she enjoys television