I've just started a refurb on an s10+
I seemed to have been too hasty on removing the front screen.
I failed to deactivate the screen.
Also there is a metal foil stuck to the touchscreen beneath.
Advise please on how to backtrack.
From your description this sounds like you've peeled apart the front screen itself -- typically there's the outer glass, bonded with the digitizer (the foil), bonded with the LCD (the 'display' aspect to the Display). https://www.ifixit.com/Store/Android/Galaxy-S10-Screen/IF416-001?o=3
Also by your description it sounds like backtracking at this point is going to be problem if you started from the front to tear down this phone instead of the proper way starting from the back: https://www.ifixit.com/Guide/Samsung+Galaxy+S10++Screen+Replacement/136889
If that is the case, coming from the front there's a chance. H vital connections (ribbon cables and such) between the Display assembly and the logic board weren't cleanly separated. How far down did you disassemble things? If it's just a matter where the Display assembly is ripped apart than you can still just go about tearing the phone down starting from the back. The Display assembly will have to be replaced as a unit anyway.