Answer:
When it's with Currys.
So we bought a printer from Currys for £59.99, safe in the knowledge that (quote from Currys website):
//// You won't get it cheaper. Full stop. We'll price match any product against any other retailer, online or instore. ////
https://www.currys.co.uk/gbuk/help-and-services/shopping-with-us/price-promise-14-commercial.html
You can still price match after purchasing an item at Currys and finding it cheaper elsewhere. We've since found it in Tesco for £49.50 and have contacted Currys - you have up to 7 days to contact them to escalate a price match guarantee. However, Tesco electrical is not online, so we took pictures of the item along with bar codes, price labels ,etc, as we knew that Currys wouldn't be able to check online. Currys have now come back and said that they only price match promise for items found online, as they need to check the items online. Well we've given them all the pictures and asked them where it says that they only match prices found online. The advertisement is VERY misleading at the very least in my opinion. They are sticking to their guns and refusing to refund the difference - their defence is that they can't price match any items not online, as they're unable to verify them.
I'm still scratching my head here ..... am I the only one thinking that this is VERY misleading?
Anyway, this is no longer about the money .... it's a matter of principle and I'm wondering if it would be a worthwhile venture to complain to the Advertising Standards Authority. All I'd want is for the advert to be changed/reworded, so others don't end up in the same position as us.