Car appreciation... the aesthetics, the engineering, etc

The motorbike/scooter thread has become a bit of a general discussion thread where mechanical advice has been sought, and given. Is it kosher to ask car mechanic questions in here?

i don't see why not, although there is probably about three people that actually wield a spanner.

Electrical problem anyway so the spanners can go away!

I have a 2005 Punto 1.2.

Way back when it was freezing I came out to it one morning and the clock had reset and it really struggled to start, bit of trouble starting another couple times so I intended to get it serviced and get a new battery. Took it for the service and was told the sump was porous (rusted to fuck) and they wanted too much to fix it. Took it away and got a mechanic neighbor to do the sump and the new, thinner oil seemed to make it start a lot more easily so I forgot about the battery.

Fast forward a couple months and the car takes me to work no problem but when I get in to go home, battery light on dash is on (from here on if there's any power in the car, this light will be on) no power steering and a whine from the engine (I now believe this to be the alternator) turned it off and restarted, no whine but still no power steering. Stop at shops on way home and car won't restart, dash lights up like a christmas tree (steering, engine, battery, airbag warning lights all on) then it dies completely. Went in and got shopping, came back out and it started, just. Some dash lights still on).

Next day, check it, starting fine but still no power steering, use it for a 5 minute journey, fine, few hours later jump back in it, trouble starting, runs for 5-10 minutes but dash starts lighting up then splutters and dies - no lights, no dash, no central locking, dead.

Walk home, get a mate to take me back to it with a towrope/jump leads but it starts itself, gets me home then splutters and dies.

Starts no bother with jump leads but the power steering hasn't returned and there's still loads of warning lights on.

I'm thinking alternator and/or regulator is fuxxored? Definitely think it's more than just a flat battery as shirley jump starting would return car to normal if it was?