Reason for the move is Sky will not allow customers own router (Vigor 2760) will Zen support this?
Actually you can use your own router on Sky ADSL services now (thanks to the O2 acquisition) but you won't get support unless you use the Sky router. No idea about FTTC, but there are ways around that: http://www.skyuser.co.uk/forum/extracting-sky-router...
JamesBT Infinity 2 19/09/2012 - Sold 42/6 - Getting 49/8.5 - Sync 53 / 9.5 Mbps @ 470m approx 14 years of broadband (ntl: cable to BT FTTC) - Router: Asus RT-N66U - Modem: Huawei HG612 speedtest
Zen's usual unofficial stance is they will support any CPE.
If you remove the OR modem and use the VDSL modem built into your router it will work, however if there is a line fault however, you will likely be expected to replace the OR modem until the fault is resolved.