Just looked on you tube and surprisingly there's no stripdown guide.

Here is a seal kit-

http://sheffieldairrifles.co.uk/comp...t-p-74259.html

And another kit, just for the atomic which is a better bet.

https://spares.bagnallandkirkwood.co...eal-kit-brok3/

Can't find a specific parts diagram, but found one for a compact rifle made by brocock which seems to have a similar action. Useful for stripdown

https://spares.bagnallandkirkwood.co...ed-Diagram.pdf