In article om,
TrailRat wrote:

Any ideas or links to products on the market? I'm UK based, so any
products, I'd prefer to have them based here please.

A house-door type lock, of the "spring-latch" rather than deadbolt
variety. You leave it unlocked, you hope you can convince the postie to
be nice enough to spring the latch and close the door when packages are
delivered, and then you hope the package thieves are not overly
determined. A lip covering the seam between door and jamb will help with
the classic "credit card attack" on cheap spring locks.

--
Cats, coffee, chocolate...vices to live by