Should we plan some days in England in conjunction with our trip to East Africa?

I would be tempted to use points to get into London and book a separate flight from there. As long as you are vaccinated, covid rules for England have been mostly relaxed. Yes, Cornwall in July/August is too busy to be pleasant.
Margaret

Under the “appreciate any comments” category, did you look at Delta miles to Johannesburg? Then your separate ticket is much shorter, likely a lot cheaper. In addition to Johannesburg, Delta also flies Atlanta to Lagos which is closer still, but I’m not sure you want to deal with Nigeria.

Checking now JNB from JAX is pretty reasonable at 120,000 points RT. Lagos is a third more.

Note that Paris or Amsterdam are the
Logical stopovers using Delta miles, I don’t think London is possible, unless you can connect to SkyTeam partner Kenya Airways from London. I would ask on Flyertalk if there’s a back door way to book with Delta miles via phone or the Kenya Airways site.

I don’t know what is going on with KLM, but flights to India starting Delta to Amsterdam changing to KLM seem non-existent, and KLM would be the likely connection to East Africa.

I'd have thought that a stopover would add a layer of risk, and I know how much the safari has meant to you.

If we weren't in the last two years I'd say come on over and stay a while and then move south to Africa.

I would encourage you to price your flight completely using $$ before you make a final decision. It has been several years, but at the time that I went to Rwanda, it cost the exact same amount to fly to Africa as it did to Europe even with the addition of the second 9 hour flight. (I used KLM) In my case, I had a several day layover in Amsterdam on my way home for the same airfare that just flying to Amsterdam RT would have cost.

I would do your time in the UK on the way home. That way you still enjoy the stopover, but you are eliminating that last minute extra exposure prior to your safari.

All good comments, thanks.

I did price the complete ticket to Africa and return and price was $2100, which was much higher than what I expected. That price ran was an open jaw, since our safari starts in Nairobi and ends in Kilimanjaro. A RT to Nairobi is less, but that would require a separate one way ticket from JRO to NAI and add complications.

We don't want to go via Nigeria or South Africa. That might require even another COVID19 test.

Perhaps I should consider a short stay in London (1 or 2 days) prior to flying to Africa, then spending a week or more in England on the way home. Still, that would require another COVID19 test. I suppose we could just stay at a hotel in Heathrow for one night on the way over and limit exposure to COVID19.

Are COVID19 tests available at Heathrow?