The sprung seats on our Troll were a nonsense, so I shopped around for a top quality foam replacement.
I visited a couple of big places in Bristol but their prices were sky high. Very impressive was the http://www.cbscc.co.uk/
where I tried the firm foam with a memory foam cap laminate, I found that at 4" thick the old beefbones easily found
the 9mm birch ply beneath. I looked again and found http://www.thefoamshop.co.uk/ I ordered a 5" grey foam.deluxe,
polyester wrapped and net covered.
Leaving the rest of the seating foam and backs at 4" the new seating foam does not look out of place and when recovered
with the same flame retardant, teflon coated, dirt resistant,green and gold material it looks superb.