Disappointment!

Looking forward to a ride-out with a couple of rider friends this morning. I've suspected that my battery would need replacing soon so I had it on charge with the charger/conditioner for two days, took it off charge yesterday afternoon.
This morning it was quite cold so got my warm gear on, pushed the bike out at 8 o'clock, helmet and gloves on, ignition, but we didn't have lift-off! It turned once and died on me.
I think it is the original battery, as it is Harley branded, so I think it's not done too bad to get 6 years out of it.
I'll get a new battery tomorrow. At least this time I didn't set the alarm off. If you disconnect the battery, or anything electrical, without removing the main fuse first, the piercing alarm goes off! Procedure is, switch on the ignition, remove the side cover, find the main fuse and pull it out. Everything goes dead but no alarm.