If you've really got 1p, 2p, 5p, 10p, 20p coins from 1947, it'll be a miracle! We didn't use decimal currency until 1971 ;-)
There are plenty of people who
try to sell old coins on eBay, e.g.
https://tinyurl.com/bdz37j2b
but that doesn't necessarily mean that there are any buyers for their offers. I'd be tempted to offer the whole lot in a single eBay auction sale, with a starting price of around their total face value.
However what I think that I'd actually end up doing is donating them to the RNIB:
https://www.rnib.org.uk/get-involved/fundraise/do-your-own-fundraising/foreign-and-old-currency/