We've been with Zen for 15 years or so, but not had anything from them about this change
I've just been forcibly upgraded from copper to CityFibre by Zen (Thursday last week). I thought I might be losing my /29 which I've had since 2002 but that transferred without a problem, as did my /48 IPv6.Technically the switch was utterly painless, and as they initiated the upgrade I'm supposed to only be paying the same as my old FTTC link (£19.50/month rather than the full cost which I think is £35/month).
However, they've totally bogged up the billing. As they started it I shouldn't have to be paying an extra penny, but they're trying to get me to pay £2200(*) for the upgrade! There is a support case open on this but they're being very slow to respond. (I wonder why?)
(*) They've managed to enter my annual fee as a monthly one and are treating the upgrade as if I requested it.