Flat battery

Hi just been up to my transit duet to to give it run and the battery didn't have enough poke to fire the engine up so I plugged in a solar panel and left it till the new year to sort it out somehow - but I was thinking could you put jump leads on the leisure battery and use that to start it as I used to do on my narrow boat. Also does a solar panel plugged into the cigarette lighter socket achieve anything. I would be glad of any help as I am new to this

I would've thought a small solar panel would do little to charge a flat battery at this time of year. And nothing at all if the cigarette lighter socket is of the type that is only live when the ignition is on!
Regarding starting the vehicle with jump leads from the leisure battery, although I've never done it myself, I do know of folk who have, and apparently have done so with no ill effects.
The best option would have been to remove the vehicle battery and fully charge it back at your house.
Al.

Most motorhome leisure batteries will quote a cranking current and, if fully charged and disconnected from the habitation circuits, would facilitate a jump start. A deep cycle leisure battery will not. If you are not confident in the capabilities of your leisure battery then do not try it or you could end up with two duff batteries.