@mjanesuk
Definitely incompetence.
from all you've written, I wouldn't bother getting them back.
Keep the 3k and a get a good local installer to come and fix it.
At 3k we'll come from Worcester to fix it and do it properly for you!
The system need taking off the roof.
The top pair of rails are too close to the edges of the panels (top and bottom)
The bottom row generally shouldn't be fixed on the short edge the way round this is to cross rail it.
There should be at least two screws per fixings.
Noggings or adding to the width of the rafter - either should suffice.
The DC cable should be clipped at regular spacing, and needs trimming and fixing.
Depending on what the actual model of the panel is 1 string of 10 modules may be over voltage for the inverter, so would need to be two strings of 5, the landscape panels x 6 should go on the second mpp tracker.
Looks like either a schuco or a grey import 4000TL, it probably also hasn't been properly configured for the UK, so that will aslo need doing / checking, and if it's been generating for > 10 hours will need a bluetooth link and a GridGuard code to do it.
I condemned this installation that was fixed by the customers roofing contractor as it was a brand new roof and they didn't want us to screw to it - I refused to issue the MCS certificate until it was fixed to my satsifaction - we supplied the s/s tray for the roof and installed the cable, they bodged the fixing, note the number and spacing of cable ties that we put in ... if they'd let us do what we had propsed they'd actaully have had a better jobdoen in the first place and it would have cost them less - next time they'll let us do it!
We've just done the snagging list on over 200kWp for that client (which we installed in just 3 weeks
)and the only thing he could come up with was that we could have trimmed some of our rails shorter ...
Also - don't let them take the scaffold down yet - deny the scaffolder access to your property until it is fixed.
Hope that helps.
Don't pay the balance ! Get someone else in that knows what they are doing.