My partner and I have been dancing for 4 years. She had never danced before, I had a little.
We dance at least twice a week and frequently 3.
We both love dancing. Unfortunately my partner suffers from sore feet. The skin on the soles of her feet quickly becomes sore, resulting in a very painful burning sensation. She has tried 'BOB' socks, but apart from the fact she says there for old fogies. (We are late 40's)they do not work.
Does anybody out there have a suggestion for her please

Personally, I am more comfortable dancing with bare feet in my shoes. Does your partner wear practice shoes? The low heel might help.

Do her shoes fit correctly and provide enough support? Her feet will get stronger with time but she first needs to make sure that she has the right shoes in the right size for her.

Most of the professionals who are on their feet all day wear a type of practise shoe which looks like a jogging shoe with an arch in the sole.They are a unisex shoe Must be tried on I take an 8 but in that shoe 11.1/2. is the size. Latin or Ballroom wear them for training in. Can also be worn outside. I believe they are originally Jazz Ballet Shoes. There is no trouble spinning in them. Cost here $129.

Her feet will improve with time, but it might be worth going to a foot specialist because her feet really shouldn't be sore with that amount of dancing.
You could also try these soft insoles (made of spongy rubber or gel-type material)in some practice shoes. Forget this "must be right on the floor with the soles" business unless you're championship-grade dancers.
Supadance make excellent practice shoes, but your partner will still need the inserts for comfort.