2. drove another 500m until safe place to stop, engine down on power.
3. Idle sounding pretty bad and jumping around 700-1000rpm at this point.
Wow, I’m surprised your car went at all after it jumped, when mine went all I got was a series of bangs, the dash lighting up like a christmas tree and ominous silence at 70mph (in the outside lane of the M1). I put dents in the pistons and bent every valve.
Mine was an old renault megane, and I think it came to about £700 in parts, no labour as me and my Dad did the work, fortunately he’s a mechanic.
Parts were only a reconditioned head/belt/tensioner/sundries, as we did it on the cheap, had a bit of a knock on the bottom end, but put another 10000 miles on it (at 100 miles a day commute) before it got traded in and became somebody else’s problem.