Speed drop on fibre

Had 40/20 FTTC installed today. Instal was OK though Kelly man's idea of a good job was to fix the master socket to the wall with a single screw. OR supplied a HG612 modem, PN supplied a Sagem 2704N router.

Immediately after instal I used the TBB speed tester which showed 37Mb/s down, 18 up. Wired ethernet from router to PC. Samknows said my line was OK for well over 60Mb/s on FTTC so these figures are about what I'd expect.

Unplugged everything, screwed master socket to wall properly, tidied up wiring and reconnected everything. Now getting 12 down, 16 up. Depowered modem for a minute and reconnected. No improvement.

i'd give the line stats if I could but I haven't hacked the HG612.

Any ideas? I'll leave it for a day or so to see if it settles but I'm not exactly holding my breath.

Same speeds still from the test socket?

If moving full master including back plate possible that one wire is loose, is the phone working perfectly and clear?

Voice line is fine. I'll have to dig out an RJ11 to BT adaptor lead or microfilter to connect to test socket.

Found a microfilter and connected to test socket. Doesn't help.

Make sure he hasn't left star wiring, with a junction box and extension coming off the incoming line before the master socket. Extension may be telephone, or old builtin alarm or Sky box.

Definitely no problems like that. It's straight from a box outside the house to the master socket. Last time I had a line problem the OR guy remade the connections in the box outside.

In tidying up the wiring, you haven't clipped/tied any together have you? Or ended up with a cable going very close to the modem power plug?

The RJ11 lead is coiled up to keep it neat, but it was like that from the start when the speed was good. The power plugs are well away from the signal wiring.

Have you tried the IP Profile checks, i.e. http://speedtest.btwholesale.com that will mirror your sync speed, and if that is still good suggests an oddity with the PlusNet profile mirroring.

Same result on the BT Wholesale test as the TBB test.

I wish I could get at the modem to see sync speed, SNR etc, like in the good old days of ADSL where it was easy to get the stats.. As a result I've no idea if it's a VDSL sync speed problem or something at PN's end. Not willing to hack my fibre modem just yet.