Nearly every warning light came on....

A short drive home along a country road and nearly every warning light came on, "TS", "ABS", "SRS", The rear up light, battery light "M & S" and probably more, gear light started flashing (auto), wouldn't change out of "D" it just flashed. Hazzard lights wouldn't come on and then after 5 minutes the dash lights cut out and the main lights dipped dramatically. Then we met a gritting lorry....no accident luckily enough! Lights perked back to normal after 8 minutes but warning lights still flashing up on dash. Got back home and no idea what to do???? okay it is -8 outside but surely this shouldn't be happening. Where do I start?

By charging the battery back up,then having the alternator tested - think you will find it has chucked its toys out.

+1 for charging the battery and it will need at least an overnight charge.

I'm having the spare alternator tested today, if it's all okay I'll need to have it put in. How big is the job, my local garage is very busy and won't say how much it will cost to do it hence I'm tempted to do it myself. My Haynes manual is packed away so I'd need a breakdown of what to take out to reach the alternator and any potential clangers I might get?

Spare alternated all tested and okay, just read up on the Rave that one should:
1) remove the viscous fan
2)Remove auxillary drive belt
3)Remove drive belt tensioner
4) various bolts
5) Vacuum hose.

Questions. 1) Does one work from above or beneath the Disco? 2) Should there be two doing this job or can I do it on my own? 3) When putting new one back on any new parts needed?