coming round the M25 last Saturday following an Austrian pulling a Kogel trailer.
As our limiters were more or less identical I was on his tail for several miles so I had the opportunity to study his trailer.
It was a cross between a tilt trailer as us older boys know them,and a curtain sider.
It had sliding curtains,but it also had sideboards,and the curtains had the usual tensioners at each end,but also hung just below the top of the sideboards with a row of eyelets along the bottom that fitted onto hoops on the sideboards,with a tilt cord through them.
I suspect it had a sliding roof also.What we would have done for a trailer like this on M/E work 35 years ago!
is that sour grapes ian 
it kept you all fit them old tilts 