Advice needed

[Mups]

There is also a foam spray you can buy.   
My neighbour used it a couple of years back, and it seemed to work.

https://doff.co.uk/product/dp1074/

[Scrumpy]

Thank you Mups..

Fortunately it is not my main shed.. It is where I store my paint and outside chairs..
It is not as tall as a regular shed..
I watched this morning and they fly under the shed .. It is raised off the ground... 
I reckon they have a nest inside the shed...

[Dextrous63]

I'd start off by putting something citrus smelling in there as they don't like that and may leave of their own accord.

[klondike]

I'd use what you've already bought - I reckon it will be more than enough to get the job done.