Managed to book two rooms in different holiday inns at heathrow

We booked one room and at last minute fatherinlaw decided to stay at heathrow night before as well.
So went online and booked another room not realising it was a different holiday inn.
We got to the 1st holiday inn and presented voucher. They said we were at the wrong holiday inn and to go to the one at other end on Sipson road.
We then went to the other holiday inn and this time somehow presented them with the other holiday inn voucher and were told we were at the wrong holiday inn and to go to the other one at end of sipson road.
All rather embarrassing
As they were franchises they couldnt simply switch to two rooms in the one hotel

So fatherinlaw checked into his holiday inn and we made our way back to the 1st holiday inn to find we'd been upgraded to a two room suite
We did have to laugh in the end