Seat reservations possible Dublin-Manulla?

[MOH]

Got the train to Ballina on Friday.

Booked online Thursday night, with two seat reservations in coach C for the Dublin-Manulla leg (oddly, no reservation possible for the return on sunday). Printed off the tickets form the collection machine in Hueston, seat number clearly printed on the tickets.

As I walked up the platofrm in Heuston, asked an IE employee where coach C was. He told me which carriage it was, said I would see some guys 'in white T-shirts'. Found coach C, no sign of any white T-shirts, found our seats where two people were about to sit down. No indication anywhere that the seats were reserved. Told them we had booked the seats, they seemed a bit surprised but moved no problem, ended sitting opposite us.

When the ticket inspector came around, complained that the seats hadn't been reserved. He told me that you can't reserve seats on the Mayo line, only possible on the Dublin-Cork line. Which made me look like either a liar or a fool to the two people opposite me who I'd asked to move.

Can someone confirm whether it is possible to reserve seats Dublin-Manulla/Westport?

On the way back on Sunday the train was roasting, no air conditioning. Ticket inspector advised that the snack car would not be open until a staff member joined in Athlone, so you couldn't even get a drink of water. when it did open, they'd no beer or tea/coffee becasue they'd no hot water.