wrong currency geotag

Our website it showing the incorrect currency. For example, visitors in the UK are seeing either USD or Euros when loading certain product pages. This is random and will sometimes show the correct currency, and sometimes not.

I have checked all back end settings and the correct currency is set for each country on the back end.

here is an example product page: https://www.techsilver.co.uk/product/grandpad-tablet-for-elderly/

Please investigate urgently as customers are not converting, as they think they’re on an international website.