Bless you Neil - it was a great pleasure to see you then! Likewise i find your artwork quite enthralling - as well as you modelling stuff exquisite!
The 4mm yard layout at Warley was very well done, and justifiably popular. The general problem with radio control in 4mm is that it is often a little bit racy - although the larger vehicles on that layout were nicely sedate. I recently converted a 4mm Bedford TK to see if I could get the slow speed and steering characteristics in 4mm as I can in 7mm. I chose the TK to be a direct comparison to the 7mm version that I had done. It worked very well.
As always, the battery is beneath the load bed, so the lorry can carry a ful load and be put to use.