If you have limited mobility, I wouldn’t think about leaving the airport. Even if you catch an Uber to Windsor, there isn’t much to do apart from walk around the town centre. There are very few restaurant options close to Heathrow, the choice in the terminals is much better.

For your return, I’d be happy with the short connection. If you are late in and you miss it, you’ll just be late arriving home. It’s not as if your whole vacation itinerary is messed up. BA are obliged to put you on the next available flight, and you know there is at least one layer that day.