Fobs not opening car

[BevanC]

Both of my key fobs have stopped opening/locking my Astra J ST. I've tried resyncing, but nothing happens, as if there's no signal, but it's unlikely that both fobs would go at the same time so I doubt it's the batteries and it's not external interference because it happens everywhere I park. Using the key in the door only unlocks the driver door, but when I lock it, and other doors are unlocked, it locks them all. The button on the dash still works to unlock/lock all doors, so I don't think it's a problem with the central locking system per se. Could it be a blown fuse to the receiver, or is something wrong with the receiver itself?  If the latter, can I check it myself, is it a dealer only thing, or will my local garage have the equipment?  It may be a coincidence, but the day before this started, while I was driving, the odometer and dash lights briefly died, before coming back a couple of seconds later (which was worrying, but hasn't happened since).  Any help would be greatly received.