My enthusiasm for further investigation dwindled with the battery voltage...
Both battery and starter pack on around 12v, charged up the starter pack,put it back on solar trickle and assumed the battery was past the sell by date so I ordered another Motobatt unit and starter solenoid.
Sodding thing fired up instantly today....(showing 12.14v)
Out for a few hours today, parked the bike up,walked the dog for an hour and then measured across the terminals on my return 12.83v.
Nothing wrong with the charging circuit then !
Will check the battery voltage as the bike is parked up to see if I have a drain to earth.
New battery and solenoid arrive this week, well I'll have some spares in the cupboard
