Here's another of Per Nystrom - perhaps with the same bike as featured earlier. It comes from a 1927 edition of the Swedish magazine Motornyheterna and the caption probably says 'Per Nystrom with his factory Norton. The cycle parts are probably from a 1926 model'. OP1853 is a Birmingham registration number.
The front brake is not connected and there is no oil tank atall! But look carefully and you'll see the manual oil pump fitted in the petrol tank - just below his right hand. Perhaps he was using the bike for sprints - or something similar - and was not using the automatic oil pump in the crank case. The tank would need to be from an earlier OHV bike ('23-ish?) where no separate oil tank was fitted. This would also explain use of the Dance grips on a strap. These were made by the John Bull Rubber company and one could buy them with the strap - or to go on the more usual mounting plates on the tank.
Although the picture is only a photocopy and lacking clarity, it looks as if the bike still has beaded edge rims which would be likely if it was a Model 25 but less likely if it was one of the 1926 Works bikes which sported 21 x 3 wired on tyres back and front. Compared to the other Nystrom photo, the carb. looks different but the Dance knee grips seem to be the same. You will notice the hand written comments....... who's got it now??