S,
I bought it from a Halfords in the Netherlands.
It is a Romer King Isofix. They do have a four point harness (fixed to the child seat) but the seat itself can be attached with either a conventional seatbelt or a lapbelt only.
FD
Just got the paperwork out:
Romer King (with the umlaut points on the o but cannot find that on the keyboard)
www.britax-roemer.de