Rent Tarion EVF Loupe DSLR Viewfinder in Glasgow (rent for £5.00 / day, £2.86 / week)
Using a Viewfinder or Loupe - YouTube
Dpofirs 3X Magnifier Viewfinder For 3in 3.2in Camera Camcorder, Professional Camera Viewfinder For Macro Shooting Observation wiht 1/4in, 3/8in: Amazon.co.uk: Electronics & Photo
BeMatik - Parasol and eye loupe LCD for Nikon D800