SII Disco, Bumpers and spoiler

Hi all,
My 2000 TD5, had it for 6 yrs now and reading some of the threads here I reckon I must have a good one. Only real trouble has been the injector loom (new loom, sorted for now). A couple of years ago (after a frightened horse kicked seven bells out of the front bumper) I bought and fitted a Bearmach steel winch bumper, (no winch ), it seems right that Land Rovers should have steel bumpers, and I didn't fancy paying out about the same money for more plastic. It was the only one (and still is?) that looks right and is shaped nicely. The bumper has been great apart from poor original coating or paint and the fact that the washer bottle needed protecting (If anyone has seen any novel solutions to that problem I would love know).
Approach angle is naturally much improved, but as the vehicle only drives across the local fields and pulls the horse box around I am more interested in restoring its Motorway stability so I want to add a spoiler, I thought of using an MXC 6828 style one from a RR, keeping it in the family parts bin. Has anyone out there ever tried it or similar, I reckon it must be about the right width??
Also love to find a steel back bumper, anyone know of a nice one??

A spoiler? a rear spoiler? for a disco? what speeds do you do that you might think you need a spoiler?
or do you mean a big spoiler like lorries have to deflect wind over the horsebox?

Sorry for the confusion, the spoiler is for the front Bearmach winch bumper..... at the opposite end to the original and now somewhat battered rear bumper. It is quite noticable how light the steering is over about 110km/h on the motorway, and I am sure the mpg suffers.