My battery doesn't seem to be charging correctly. On Monday morning I had the RAC to come and jump start and he run some tests but said the battery seemed fine and it was charging up (whilst he was there). Done a few 30-45 min runs in it this week but tried this morning (Friday) and it's dead again.
I'm actually surprised the RAC did say it was fine as I was expecting the whole sales pitch.

Do I just need an extra long journey to fully charge it up? 1-2hr? RRS HSE TDV6 Autobiography

What voltage is the alternator outputting? Ditto battery? How old is the battery?

It really needs a good run on a charger, at least, as it takes an extremely long drive to fully charge it.  Visiting from DISCO3.CO.UK
2006 Discovery 3 TDV6 Auto HSE Zambezi Silver

I tried hooking up a solar panel trickle charger I had spare from years ago but I don't think it has any effect

I'll purchase a mains charger then. I'm driving it less and less now I have a little weekend toy RRS HSE TDV6 Autobiography

A smart charger (CTEK being very popular) is always a worthwhile investment, IMO.

Do check/keep an eye on your alternator though, in case it is at fault. If the bettery drops when the car is left alone, also consider a current drain.  Visiting from DISCO3.CO.UK
2006 Discovery 3 TDV6 Auto HSE Zambezi Silver

OK great. Just read I can use the CTEK to charge through the tow electrics
Ordered thanks RRS HSE TDV6 Autobiography