Basic car battery charger

[Yellow Saddle]

No, but it'll top the battery up so the car will drive half a mile without immediately conking out again en route

Even half a mile could be costly. Without water circulating, you'll blow a head gasket quicker than you think.

 

[DRM]

Even half a mile could be costly. Without water circulating, you'll blow a head gasket quicker than you think.

This with the caveat that it's just an alternator belt, and the water pump is driven by another belt, however the O.P has confirmed it was overheating getting back home

 

[Jenkins]

Even half a mile could be costly. Without water circulating, you'll blow a head gasket quicker than you think.

I guess I'll find out if any head gasket problems are found as part of the MOT/service/belt replacement. I had no option as there was no way I was parking in a layby on that road (a good choice as it turned out due to the problems I had with the RAC).