Failure!

Today was all planned out with three veterans funerals at 11:00, 13:30 and 15:30. I had planned to attend all three, escorting the cortege with two other RBL Riders.
First of all I had to chase up the details for the 11:00 funeral. Turned out the family had not responded to the RBL chap that organises them so that one was cancelled.
In the meantime, I checked the bikes tyre pressures, lights, indicators, fluids etc. All was ok, just 3 or 4 lbs to top up the tyres to the correct spec.
I have a gadget, on the handlebars, that gives me 2 x USB sockets plus a 12v 'Cigarette Lighter' socket, not much use on a motorbike really but handy for plugging in my air compressor to top up the tyres.
All done, even started the bike up for a few seconds to ensure it was ok after lying idle for about 2 weeks. Only problem is that I left my power accessory switched on (the USB and 12v).
14:45 I got my bike gear on, it's getting quite chilly today, flags on the bike (it was an RN submariners funeral), gloves on and - Nothing except a pathetic clattering and silence! Yes, the bit of power that started it previously had been drained away by leaving the power accessory on.
I took the seat off and connected my battery pack starter, no good as I hadn't used it for weeks and it was not fully charged up so I put the bike battery on charge but it was never going to be ready for the 13:30 funeral.
I let my friend know by sending him a message, sorry I was letting him down. The other, third person, had already told us this morning that she wasn't going to make it.
After being on charge for 1.5 hours I tried it again, zilch, zada, nothing, well not starting anyway, just a lot of clattering again.
Told him I wasn't going to make it for the 3rd funeral either.
He carried on by himself, escorting the hearse the short distance to the crematorium, twice, and even changing flags (which I'd planned to do also) as the third funeral was an old lady who was a Flt Lt in the RAF.
After being on charge for nearly five hours I tried the bike, and yippeeee, it started so it's ok for tomorrows ride-out into Herefordshire (HR4K) which is owned and run by a veteran of 22 SAS 'The Regiment'. Should be a good run-out but I have not stopped apologising for letting down my brother rider, RBL City Branch, the deceased veterans and all. Everyone says it's fine, these things happen, but I felt very bad about not being prepared, especially after I thought I was. Must be more careful and thoughtful in the future.
P.S. and yes, I have kept the battery charger/conditioner on until tomorrow morning!