[urq] centre seat belts Parts 1 and 2

[spot.ontheroad]

Part 1.
I live in the UK and own a RHD 1987 WR quattro. I also have a very understanding girlfriend and three lovely little children (three being the maximum if ur-quattro ownership is to be maintained!). At the moment the youngest has a child seat which is restrained using the centre lap belt, the seat itself having a full harness, but she will shortly out grow this and I do not like single lap belts so I intend to fit a 4-way Willans harness in the centre position to secure our little treasure. Has anyone else fitted a full harness in the rear of a quattro and if so what were the pitfalls/problems? I intend to mount the top straps under the rear parcel shelf if at all possible.

This brings me on to part 2.
Our other car is a 1992 A100 Avant. This too has only a lap belt in the centre rear position. Has anyone tried to do a similar thing with one of these? I don't know anything about US spec cars but sometimes they have different rules regarding belts - do US A100 avants of 1992 - 96ish vintage have a centre lap or lap/shoulder belt? Look forward to any guidance on this.
All the best

Keith

'87 WR

p.s. I've then got to sort something for the 1963 Daimler V8 so we can all go out in that. No seatbelts at all in that baby....yet.