First as Gromit spin the gnome sign so it is pond side up and place the badminton racket from Wallace's room into the other gnomes hand.
Then after this is done go next to the major and i recommend exiting the game so it saves (not through guide) so if you fail you exit through the guide and load the game up again.
First shoot the dustbin, the tree (that miss Flitt is stuck in)and the shed door.
A bee will move above the dustbin so when it does shoot it and it will fall into it, then shoot the squirrel on the branch who will knock the lid on top of the bin. 1/3 down.
Secondly shoot the bee who circles above the pond. once you have hit him shoot the stop sign held by the gnome and this will be another bee down.
Lastly shoot the bee who circles over the wrong trousers from the shed so he will land in them. Shoot the trousers and they will return to the shed. All 3 down.
Happy shooting and good luck.
I had no idea about bookmarks on my play-through but to make this even easier, look at Dude rain's comment below.