I doubt you'll find it on a dating site.
I was once commissioned to write an article on such sites and my research showed that most (although not all) people were disappointed.
Men were looking for sex and/or someone to look after them (if they were older) and women wanted companionship more than sex. This is, of course, a generalisation based on a number of interviews.
The conclusion was that long-term face to face relationships, and not just the hit-and-miss dating and hoping, work better.
I suggest you look at what groups are available for people over 50 in your area and try to join a few.
If, as you say, you are slightly disabled, then that broadens the field as well, as there are also clubs catering to those needs. At least where I live.
Here are some websites which may help:
www.ageuk.org.uk/
grey-power.org.uk/
But as I am not in the UK now, I rely on other GNetters to give more accurate information.
Best of luck