Pyjamarama: hints/cheats

This is the complete solution.

1) Get the Bucket and fill it at the bathroom tap.

2) Get the Plant Pot and head to the room containing the
fly-traps.

3) Swap the BP Can for the bucket of water.

4) Get the triangle key from Floor 3.

5) Go to Floor 1 and fill the BP Can at the petrol pump.

6) Get the pound coin and swap it for the penny.

7) Enter the now unlocked Toilet and get the hammer.

8) Swap the hammer for the fire extinguisher in the lift room.

9) Go to floor 3 and find the room containing the pile of tea
chests.

10) Climb up the chests and exit through the window.

11) Continue past fire and quickly get the square key.

12) Enter the unlocked snooker room and get the laser gun.

13) With triangle key and laser gun, go to Floor 1.

14) Go past the pump room and take, then drop the battery. 

15) With the Bp Can and the Full Laser Gun go to Floor 3.

16) Enter the rocket and leave the laser gun on the moon.

17) Get the Ignition Keys in the roof using the Driver's License
You can get the helmet (sliding down the bannister) only if you are
carrying the blasted ignition keys, that get swapped for the helmet...
otherwise the game's unfinishable.

18) Returning to Earth, slide down the banister and get the
helmet.

19) Swap the library ticket for the library book.

20) With the helmet and the book, get the scissors.

21) Switch HELP on, and go to the room with the balloon.

22) Get the box key and swap it for the magnet.

23) Re-fill the BP Can and return to the moon with the magnet.

24) Touch the magnetic lock and get the clock key.

25) Return to Wallys Bedroom, touch the clock and you have done
it!!