High latency at peak times

Hi,
Have had a pretty solid fibre connection with Talktalk Business since April but over the last week or so getting high pings between 6pm to midnight - no packet loss though. TTB have done numerous line tests and they say no issues on my line, if there was exchange congestion that would show up on the line tests. Speeds also drop to approx 50 meg at peak times, usually get 75 meg. Any idea what the issue could be? I'm directly connected to the master socket, mk2 faceplate fitted by Quinn fella. Latest graph:
http://www.thinkbroadband.com/ping/share/7a96028627e...
Thanks

So speed tests are slowing down and latency is up? If modem connecting fine then says contention somewhere

Thanks Andrew. Can there be congestion on the fibre links to the exchange? I know Openreach are enabling fibre cabs left right & centre in the Inverness Culloden area ( BDUK) and my cab (NSICL #6) is already full, awaiting further line cards.

Each cab has at least one 1Gbps link back to the exchange, the up to 76 Mbps runs with a 30 Mbps Commit Rate, so should never contend below that on this link, i.e. a LOT higher than any ADSL2+ product.

At the fibre handover at the exchange it then all becomes TalkTalks responsibility.

Congestion on the cab links is not unheard of and if you have a neighbour on a different ISP on same cab, then should be easy to cross check latency effects.

Not many people have a TalkTalk Business BQM up and running the ones I can see show not pattern that is the same on all of them.