Another fried regulator/rectifier?

A day after the bike was starting and running OK, I went to start it and the battery was drained. I jump started it OK but the dash died then it showed a DAT Soft message, clocks reset etc. I went out for the day on it then half way through the day I noticed the indicators (all round) were flashing very quickly. The bike struggled to start the next couple of times but managed it, just. When I got home I put the battery on charge. I haven't looked at it since but a mate is coming over tomorrow with a volt meter. What should I be checking?
Any thoughts on likely cause? The regulator/rectifier went a couple of years ago and was replaced. Is it likely the same problem? If so I guess I'll get a MOSFET reg/rec.

Be getting one of these myself before such troubles occur,,,,,,,,,,,,I believe these to be "plug n play",,,,

http://www.regulatorrectifier.com/catal ... ef209657c4

At 54k miles, have only replaced battery and reg/rec once (both at same time 'cos bad battery seems to affect reg/rec and vice versa)- most of many times with similar symptoms, has been earth/wiring/connector issues - viewtopic.php?f=5&t=10424&hilit=soft+32+dat+101