Having dealt with all the 'right way up' bimbles, Sijambo was flipped over yesterday and not only did I find a compression dent or two (removed with hot air - I got the M-i-L to breathe on it!), but he has trolley rash, too. Getting rid of it is a chore but not difficult.
 
I'm less sure on how to prevent a recurrence. The trolley is a standard West Mersea with blue foam & ribbed rubber cradles. I have occasionally seen 'Astroturf' used as a cushion material, but investigation reveals a bewildering choice in pile length and resistance to weight so I'm no further forward really.
 
Anyone have any suggestions?
 
Thanks in advance.

I had similar problem a few years ago, used 30mm pile Astroturf and sealant on with 798, really strong sealant from Screwfix. Found the Astroturf discount online as it was an off cut. 

 Thanks Dale,
 
I bought some material from Welsh Harp Boat Centre (Sovereign Trailers) in the end as I couldn't work out from the direct astroturf suppliers what I needed. I used old skool EvoStik after removing the ribbed rubber fron the cradles and washing all the sand and salt away...