Night towing - narrow roads
This weekend I had my first experience of night driving with a caravan. Whilst this was no problem on dual carriages and major roads I found it was tricky on narrow country roads where there was a minimum width for two vehicles.
The problem stems from the lack of visual references. In this situation in daylight I glance in the nearside mirror to judge the proximity of the side of the caravan to the verge, followed by a glance in the offside mirror to check the position of the centre
marking on the road in relation to the offside.
At night the references are not visible!
I'm sure as I get more experienced this will be come less of a worry. However, whilst contemplating solutions to this problem I considered the addition of some under chassis blue LEDs such as used by boy racers (pimp my caravan 
). Of course these are illegal to use whilst in motion 
Trawling around the Internet I stumbled across
Amber LED side marker light with intergral reflector and mounting bracket . If two of these were mounted each side angled slightly downwards (perhaps?) would this be a) effective and b) legal?
Or does anyone have any other ideas?
Thanks.