Sounds like they are moving you from Zen backhaul to BTW.

Be interesting to see whether it improves things.

Quick update on Single Thread Download speeds.

Just about back to normal.
Within about 10Mbps of normal Single Thread Speed, just seems to fall away towards the end of the test and latency is back to normal, was up in the high 40s for most of the last couple of weeks.

Will just have to keep an eye.

An update.

They moved me to BTW network on the 5th. Things seem to be better. Will update if anything changes.

I have had the same problem with single thread download speeds in single figures. Zen have moved me over to different equipment in the exchange and speed has improved to 60mbps the same as multi thread download.
https://www.thinkbroadband.com/speedtest/15187211025...

Exactly the same issue, single thread rates have dropped to ~12 Mbps but on top of that I experience regular cuts, even during off-peak, daytime. I have contacted them and acknowledged the issue. Like the others, I will be transferred to another network in 10 days. That is quite a long time to wait considering the premium price of Zen.

I suspect the waiting time is due to Openreach. Switching a connection's backhaul probably has some kind of lead time like 10 days.

What a joke my latest speed is even slower than when I was on ADSL2+ £ 35-40 a month for a totally [censored] connection every evening !!!!

Download speedachieved during the test was - 15.27 Mbps
For your connection, the acceptable range of speedsis 40 Mbps-74.1 Mbps .
Additional Information:
IP Profile for your line is - 74.1 Mbps 25/02/18 time 20-20

Got a definitive date of migration last week: 12 of March. More than 10 business days to be honest. What is going on with Zen? Every time I had an ISP in this country it has been the same story: at the beginning very good and tech savvy, then going down the drain. At least Zen still has a good CS (they understand issues and call you back on the phone to update you) and they are still indeed tech oriented. But this is concerning.

12th March is exactly 10 business days after you posted your original message.

In reply to a post by Ixel:

I suspect the waiting time is due to Openreach. Switching a connection's backhaul probably has some kind of lead time like 10 days.

I expect it goes through a similar, if not the same, procedure as a migration, where the end user has ten working days to change their mind, (required by Ofcom), and inform the gaining ISP not to let the move go ahead.

This sort of change is in effect a migration between wholesalers, ordered by the ISP.

Ofcom regard working days as Monday - Friday. Lucky them!