Well, the PBQ battery itself fits perfectly in the C5: it clicks right into the bottom slot
and underneath the retainer strip at the back. Alas I need to modify the lid as it is too high when fitted. Inside the lid there are some plastic strips I need to cut back so the lid will sit lower on top of the battery.
![](http://i1300.photobucket.com/albums/ag99/gertk64/2013-05-05100404_zpsefe20e14.jpg)
Alas, the retainer at the back seems to grab the lower rim of the Oldham battery (which is not present on the PBQ) so I had to make a spacer of about 17 mm between the retainer and the bottom. Now it sits firmly. I have modified the lid with a Dremel tool and made two small thick brass strips with a 6mm bolt on which the original nuts fit. From the top it looks quite original.
So far so good, still the keyswitch block does not make a reliable contact, I need to wiggle it a bit to get connection.
More investigation needed.
Next step: check the 'grease status' of the motor, wheels, steering and pedals.