New battery for the connect is almost £300. I can get a bottle battery with bracket for around £100. Can i simply connect into the existing controller if i fitted a bottle?
It can't me much worse than the one he already has/had.You can connect any battery of the correct voltage to your controller. Bear in mind £100 isn't going to buy you much in the way of quality or capacity.
No, nothing seems to reset it. It must have had it. When i’ve got the bike back together i will see how it rides on the permanent LOW setting. I may have to join up wires to get it on permanent high.It's probably got water in it.
Try unplugging it, wait a few minutes, then reconnect it to see if it resets.