I have had a prolonged period with no training. Just before this I had improved my 4DP but did very little training at the new settings.
On starting back again I have found that I am struggling with the workouts and constantly turning down the intensity.
Is there simply a way to set the 4DP results that the software will use for my workouts to a previous setting so I can build up again?
You could put them in manually of course, but wouldn’t a new FF to get accurate 4DP numbers be a better solution? Or perhaps a HM at least?
On iOS if you go into workouts and search for ‘full’, this should bring up all your previous full frontal sessions. Pick the one you want, then click apply to my 4DP profile
Or just do full frontal again 
Of course you’re right but because I’ve got 2 weeks into a plan manually adjusting intensity it just occurred to me I may be able to go back a test.
I really should have just done a test before starting this plan.
Yes it should really do the test.
The option isn’t available on windows
Sadly,/happily, it is on Windows. Go into Passport, and you should have your 4DP history there. Underneath the chart are a number of circles surrounded by ‘prev’ and ‘next’. I can cycle through all my 4DP tests, and choose to apply 4DP profile from any of them. The text is in turquise/blue above the chart
You may have to delete the plan and reload it if the test gave you a different rider type, or different strenght/weakness
Don’t get me wrong, I don’t think it is a bad idea, however it could be that your numbers has declined more/less than your prior FF causing you to get sub-optimal training sessions.
Why not consider switching a hard workout in the plan with FF to get accurate numbers for the rest of the plan?
Have you considered doing a new Full Frontal test? A new FF will give you the most accurate numbers to work from.