Really with a lack of resources (and the relative safety & time available), off the wall thinking became the standard for British researchers throughout the war – to the point where it practically became policy. Not all of it worked, but considering the challenges faced it's amazing how novel some of the solutions were.
https://en.wikipedia.org/wiki/Department_of_Miscellaneous_We...
https://en.wikipedia.org/wiki/Bouncing_bomb
https://en.wikipedia.org/wiki/Explosive_rat
https://en.wikipedia.org/wiki/Panjandrum
https://en.wikipedia.org/wiki/Hobart%27s_Funnies