Look on page 17 [page list at right top of forum page]
select this catagory you question is in. Look for
'THETFORD PORTA POTI BENCH TYPE WIL NOT FLUSH
My email address is on one of the replies send email I'll send instructions on how I did mine and more. UK or Australia? I've had repair info request from Aussy Spain France campers on the thetford C2. Can't include email addresses now hence the reason you have to go to page 17.
Bob
May 2009