Disco is a none starter... runs on a bump

starter relay failed?

if it were me, I`d find the low power wire to solonoid,
roughly fix a length of wire to that point, and with ignition on, flash the loose end of wire over live terminal on battery to see if starter turns over..ooops bin beat to that one..

or do you have an imoboliser transponder thingy on your key ring,
thats now missing?
as on my 200 doosel, a normal key will light all the dash, but wont let it start,
untill the correct fob with imoboliser thingy in it is near the car..

that would be next but they dont often fail unless wadeing etc