Thanks to all for your excellent responses. Good to know particularly that even an 8 ft bed can cause problems then backing up - which is the concern I had.
I also wrote to Prime Time's email address and was surprised to get a quick response - which is as follows:
Yes our Fifth wheel caps are designed to be used with a fixed hitch and a short bed truck, They are a 88 degree super turn front cap.
Regards,
BY (name removed)
Yet again after seeing the forum responses I'm sure this only applies to forward turns and that reverse backing remains a risk.
