attaching headers to silencers

[Slartibartfast]

Hi all

I have just taken my bike for its MOT and it failed on the exhaust blowing - its the bit just before the silencer on the left hand side.

I'd decided to buy a new set of headers and replace them. I've taken the old ones off and the silencers appear to just push on with the gasket rings in the middle, no clamps/springs or anything of the sort.

Is this how they're supposed to be? The end of the pipe on the silencer is looking a little ropey as well but dont really want to fork out for a full system.