Hi Glynn,
Sorry for not getting back to you, only just read the replies. Parts required are listed below:
Maplin
RD19V Rocker Switch
LF10L Box AB9
NE19V Rigid PP3 Clip
FE32K Stick-On Feet Small
RK45Y 10AA Battery Box
RS Components
341-2901 Connector,circular,Sureseal,chassis plug,4 way
167-9483 Connector,circular,Sureseal,female,4 way
167-9499 Connector,circular,Sureseal,contacts,male
? Connector,circular,Sureseal,contacts,Female
EuroBatteries.com
2500mah AA Nimh Batteries 3 packs of 4
Garmin
Gamin power cable (Look on ebay for old mains adaptor or take it from cig lighter adaptor)
Garmin Mounting plate (Should be in box with your unit else about £5 from gamin)
Hops this helps, you may want to use a different connector other then the RS ones as they can be a bit pricey.
Cheers
Ty