Seems the consensus is that it is likely a Starboard 727 wing tip, taken from a window seat, fairly forward of the (clean) wing,
and the airline in 1973 would be Dan Air.
No LE slats are down yet for the approach and landing.
The 727-100 had split lowering of the LED's; The 2 large outer LE slat sections lowered first when Flap 2 is selected,
then the inboard Krueger flaps lowered, including the other outer slat with Flap 5 IIRC.
Then these would remain out with any landing flap selected using up to Flap 40.
Some 727-100 airlines used only Flap 30 for landing, but no idea what Dan Air did.
It's not a 720B - As TCU points out that if it was we would see some pylons and engines in the window view.
We did have an idea it was also a Comet, which is credible too - Comets had curtains then BTW.
The OP mentions he went to Corfu on a Laker 1-11 too and shows us a photo.....
And many thanks for your kind comments Ladies and Gents - as you know charter and holiday airlines from this period is where for me it all started it.