Switching from Virgin cable to ADSL2+

Posting for friends who are on Virgin Media with terrible packet loss (40% even at 6am based on traceroute with mtr) so looking to switch to ADSL2+. They don't have FTTC or FTTP available despite being 850m from exchange - Upper Holloway, https://availability.samknows.com/broadband/exchange...

Speed not really important, the BT ADSL checker shows this:

WBC ADSL 2+ Up to 15.5 -- 13.5 to 17.5 Available -- -- -- --
WBC ADSL 2+ Annex M Up to 15.5 Up to 1 13.5 to 17.5 Available -- -- --

Any suggestions for an unlimited ADSL2+ provider that's really reliable and has good customer service?

- looking at maybe IDnet, Zen or Sky based on reviews here, but first two have low sample size - https://www.thinkbroadband.com/isps/compare?commit=C...
- cost is not as important as reliable service

I've had generally good experiences of reliability and customer service with Sky Broadband ADSL2+ at home (before switching to fixed wireless)

- my friends are very non-techie so good customer service and setup are also important, and I like that you can get through to UK tech support quickly with Sky.

Thanks in advance!

Sky ADSL2+ services generally do what it says on the tin and at a low price, Zen/IDNet are more prosumer focussed and this may be reflected in the information given with regards to setting up the ADSL2+ service.