Does anyone know if there is a normal post service for heavier items with tracking/insurance/signed for at a price cheaper than courier services?

It annoys me that in the US you can go anywhere and send a package at regular and non exaggerated rates, here in Jerusalem I can go to any post office and send items at any weight with variable insurance and tracked - but in the UK I can only send items up to 2kg maximum with Royal Mail, and then I have to choose between Air Sure (tracked and insurance) or International Signed for. Courier services with zero insurance and no tracking start at 50 for a 2 week service!

So if I wanted to ship matted prints from the UK, how the heck would I do it without killing myself on the postage?