Thanks, SD.
We both think the latter option is the way to go, so that's what I will do.
I didn't mention in the post but have previously taken advantage of the Netgear's superior wireless performance to connect it to the Home Hub via Ethernet with both devices being side-by-side. It was a doddle, with the Home Hub remaining the DHCP server as it will in the situation I describe, too. No need for static routes in my case.
I won't switch Home Hub wireless off this time though because I have a non-portable media server in home office that will benefit from the full strength signal. All portable wireless devices will use the Netgear (in the conservatory this time) since the signal is more than strong enough everywhere in the house and garden for such usage, though not full strength in the office.
Mains over Ethernet it is, probably Netgear jobbies.
Cheers!
XV105