In reply to a post by MrSaffron:

The cheapest and thus ideal for keeping as a hot spare is TP-Link W9970 at £34 basic wireless N router with VDSL2 modem supporting vectoring and G.INP and a Broadcom chipset. Also supports a bridge mode so can be used as a direct Openreach modem replacement.

Cost is low enough to buy one, configure it, check it works and then keep safe for back up use, or a sacrificial cheap modem in front of expensive router to give better protection from lightning killing kit.

The antenna are not detachable without some surgery, but case does open, and wire cutter and pliers will remove them.

Thanks for that info Andrew. Order already placed.

Edited by deleted (Wed 16-Mar-16 15:11:51)

Just to close out the story on BTO supplying modems... After escalating our predicament (BTO saying that had been to site when they plainly hadn't), they agreed to attend. The site is a weatherproof cabinet on a barn that will be used to host a rural community project. The engineer first tried to install a HomeHub 5, but when told this wasn't supposed to be the plan, a Huawei HG612 was found on the van - his last one apparently. He had been "asked to hand it back in", but thankfully agreed to fit it for us - top work! It sparked up beautifully and speed tested at the full 78Mb/s.
All's well that ends well - thanks everyone for your help.

Openreach will be supplying replacements for failed Openreach modems for 12 months from the withdraw of new supply (according to their briefing)

nice find.

the 8800nl looks similar to a hg612 in terms of size, but your find is cheaper.