The horn on my steering wheel has stopped working on both buttons whenever the wheel is anywhere off centre to the right. It works fine when the wheel is turned slightly left.

I had a similar problem years ago on my original hippo. It needed a new rotary coupler. I think the copper on the flexible film must just break down after a while. Back in 2006 I was able to just buy a new replacement. However fast-foward to 2015 and the part, (YRC100330 - YRC100390), is obsolete. (what happened to JLR's announcement that they were 'supporting' their heritage cars, of which the hippo was supposed to be one now).

Has anyone had any success in repairing the tracks in the coupler? - I know that there are spare tracks in the standard coupler, but I'm using all of these for steering wheel controls, otherwise I could probably have a go at swapping the wiring over.

I know it can get one from a breakers or eBay, but depending on its age, the thing could just break again a few months down the line. (My original one only lasted 3 years from being brand new).

(kicking myself for chucking the old one out, which I kept at the time, but when I sold the original hippo, threw away).

Jim

If yours is a manual gearbox? There are some spare tracks for the cruise control that you can't have

Thanks. And yes it is a manual, so I think from memory there are two spare tracks left, (two already used for the horn, and another pair for the stereo controls). Unfortunately I was intending to use the cruise control lines to run a custom switch control to run a temperature monitor / clock module I'm going to replace the factory clock with. That might be an option to consider again, and just put the switches elsewhere, (which saves me hacking a hole in the steering wheel too!). - And yes, it's annoying no cruise control option on the manuals.

Do you know if its possible to run the hippo with the airbag temporarily removed, without running into difficulties, whilst I carry out some further faultfinding/testing? (It's a pain having to keep disconnecting the battery and waiting 20 mins, and still feel very cautious about disconnecting the airbag each time.

I had the same problem and managed to use the spare connections to fix it. Never tried it without the airbag but would presume it would flag up an error unless you can find a suitable resistor to replace it with.
There should be plenty available from dead K series cars with relatively low mileage.