There are two main types here. With a gap and without a gap
WITH A GAP
The book ‘Sliding Piece Puzzles’ by L Hordern is used as the standard for all these puzzles. It is rare £20
The ’15’ puzzle was the Rubik’s puzzle of a century ago. remove the number 16 and then put the others in at random before sliding them all into order. It could only be done 50% of the time.
WITHOUT GAP
Rotos rare £5. Red and blue is a new variation on the others above. Rare £8
I really like these. Some easy, some hard.
Top 4 are worth £5 and the bottom 3 have a £12 valuation.
Larger Wisdom ball with numbers across middle £8. A fairly common puzzle £4
Rare Plywood puzzles. 6 different challenges. It is in Horden Sliding Piece Puzzle book £20
Another bead puzzle. £5