Is it possible I could get the new dual band router? I have had so many problems using a separate router for 5GHz.

I was offered the new router when I renewed my contract.

I just joined a few months ago so still in the 12 months.

Give them a call and ask if you can swap, no harm in asking.

They don't seem that high quality though, you might be better off buying your own and using it for wifi. I have the Asus RT-AC68U which works very well.

They swapped it, much better. Actually supports 802.11ac (though for some reason the staff think it just supports 802.11n). Tried using another router but got dropouts and couldn't be sure what it was, at least hyperoptic can't blame the other router now (though seems stable).

Does anyone with the new Hyperoptic 5GHZ AC router know whether it allow users to setup multiple SSIDs?

Yes, you can set up to 8 total (4 2.4GHz and 5 GHz).