Personally, I'd buy the other record. Assuming the record is you ordered was the one referenced by Pauline, by the "other" record, I mean the one on page 325.
If the GRO then send you the same record again then at least you have some data that you can question them about. They couldn't really deny sending you the same record for different record references, and they would have to explain themselves. And if they are at fault, hopefully they'd sort out the correct record and, with a bit luck, reimburse you for one of the orders.
And if the GRO send you a different record, then it may suggest that it's simple an error in their index. You'd be £7 out of pocket but at least you'd have some answers, even if they aren't the ones you want or expect.