I have bought genuine from them before, I have a feeling that in general most aftermarket versions will probably be the same one regardless of price. All the same they might be just fine.
That's what I asked you, I guess you could get the chassis acid dipped.
If that's viable I would get that done. Depends on your weather conditions if it's worth getting it painted or galvanise it.
The red/white relay trigger wire stays non live and the corresponding earth is live?
Maybe the relay is faulty, shorting out triggering itself, possible maybe?
Are you sure the starter is re-energising or is it just still running?
Aren't some glow plug relays timed, as in they stay on for certain amount of time even if engine is running.?
It is an actual Land Rover part which isn't cheap for what it is. My son has one on his Ninety, I quite like the look of them but in reality are probably pretty useless.
Why don't you draw a picture of exactly what you have wired to where for better help?
It's taken 2 pages for you to tell use that you have fitted a fuse and relay.