On 08/05/2018 10:41, Graeme wrote:

Well, I think the battery itself is OK.Â* Went for a run Thursday
afternoon to charge the battery, then left it until this morning
(Tuesday) with the earth lead disconnected.Â* Reconnected and an easy
start, from what felt like a still fully charged battery.

To recap, if parked with the battery connected, the battery is almost
flat after 48 hours, as in not enough to turn the engine to start.Â* The
courtesy light switch(es) were suspect, but same thing happens with them
disconnected.

I triedÂ* Harry's bulb trick again (small MES panel light bulb between
-ve battery terminal and earth strap), and nothing.Â* Tried using an
ammeter.Â* Nothing.Â* Yet current must be flowing somewhere.

I thought this had a 'generator' with a control box?

Some variants didn't cut-out too well, and it was not uncommon for a
substantial discharge current pass into the generator. Once battery
voltage got below 10V or so the contacts would release.

I suggest you get/borrow a DC current clamp meter to measure current
without disconnecting the battery.