Not sure if this will help but...I have also been having a hate/loathe affair with the Brant.

At first I thought it was the battery and then I realized that it is the alarm. Last night I got stranded and the RAC got me up and going again.

I had read before about disconnecting the battery and then waiting about 5-6 minutes before reconnecting the battery but the RAC tech discharged the capacitance by touching the earth battery lead to the positive. Meanwhile I sat in the car with everything turned off and held down the Zero and Star buttons on the keypad. The tech then reconnected my battery. After that, I released the two buttons and was able to run through the normal starting process. Ie key to accessories, code and then start.

I should also add that the issue I had was that the alarm was not accepting the code at first and then after a few tries, I lost all lights on the key pad.