2007 Mk6 Fiesta, only about 20k miles on it when I bought it a few years ago, now at ~40k.

Always had an intermittent starter motor problem, and by intermittent I mean like once every ~6 months, so infrequent I didn't bother to get it fixed, it always ended up starting after like 5 mins.

Last week, all of a sudden, just could not get it started. Left it for a day, tried it again. After about 3 minutes of trying, I tried pumping the accelerator while I did it. There was an almighty backfire type explosion, like a gunshot, and smoke from under the bonnet. I decided to leave it at that point and take it to the garage... 

Garage called me with the bad news today - apparently something (we assume a backfire, which they told me shouldn't even happen on modern cars) blew a hole in the inlet manifold, turning the the relatively simple £50 starter motor replacement into a £750 all-in (with labour) fix for a new inlet manifold. They've asked if I want to go ahead but have told me that, in all their years of servicing, they've never seen this happen before, or at least not without finding a cause, and they can't really diagnose why it happened until they have a working engine, hence the £700 inlet manifold. 

 

Has anybody else ever experienced something like this on a Fiesta/Ford/any modern car??! Is it normal? Does anybody know why it might have happened??

That manifold must be gold plated, loads on 'flea bay' or even a scrappy!