In reply to KS132:
As mentioned speak to the provider, generally people are pretty helpful.
A couple of points most of which have been covered.
•your pack will be slightly heavier than usual, shelters etc. Ie you’ll be carrying as though for a group.
• Whilst not every day is about big miles you generally won’t be on paths, in fact your trainer probably will make a point of it.
•Any twinges won’t have a chance to recover as you will be using your knees each day, maybe as well as speaking to the trainer speak to a sports physio and explain you want to prepare for and manage the course and your knee.
good luck, as someone moving into working their way through outdoor qualifications in their late forties creaky joint management is something we have to work around .