So I've had an email back from them. Very helpful and quick response really.
Apparently the ones I ordered the other day were 'black leather' and the ones that are £40, which I have also now ordered, are 'black rugged leather'. That does seem to be the case on the website, although the pictures look identical....!!
Anyway, I will see if the £40 turn up and if so, will send back the £100 pair which are already dispatched.