These type 063 batteries ,by "Drivemaster", are my present favourites mainly 'coz they are so cheap (about £35 ?) and seem to have put up with quite a bit of abuse over the years.
(http://i74.photobucket.com/albums/i257/1stbooboo/c5triedandtested002.jpg)
They powered most of the C5's that took place in the May'07 London-Brighton run, and have been powering my 24v "Voodoo" since May'07.
When new you could expect a range from these of about 8-10 miles. Still performing fairly well, but they are starting to "fade" now and the range has dropped accordingly.
These were eventually replaced by Halfords type 063 batteries;
http://c5alive.co.uk/forum/index.php?topic=410.0