1st time driving in the rain and I had 3 lights pop on the dash Down Hill, ABS and TC?
Is this the norm?
Turned off the car when I got home then back on and the lights were off?

 

Do a search for the "3 Amigo's".

 

But wouldn't the 3 Amigo's stay on all the time afterwords?
or until it was cleared by a scan tool?
Mine turned off with the ignition and was off when I restarted the car.

 

OK just did more research and OPTION B is in my future!

 

How many miles on your Disco? You should also consider replacing the O ring seals. Take a look at the falcon works kit:
ABS shuttle valve code solution; brake fluid leaks

 

Don't ever guess what to fix without having the codes read, there are 16 reasons for the lights to come on. In your case, since you only have a soft fault that comes and goes you need to get busy and find/repair the actual problem before the codes lock in.
Do your brakes squeak, are you wheels covered in brake dust, is your brake fluid brown?

 

No squeak, brake fluid is a tad dirty I would say 70% clear I can see through it easily and there might be some dust but I clean the wheels and sprayed it well with water the other day so as far as loose dust No!

 

Well, until you can get the codes read, when the lights are on, I wouldn't just start making repairs. The trick for you is to find a shop that has a scanner with Rover ABS software in it so you can get the codes read.