2.0 HDi bottom radiator hose removal?

[ChefExcellence]

I need to replace the radiator in my van as there is a hole in it that is currently bunged up with K-Seal. Every bottom hose I have ever removed is usually secured via either a spring clamp or a jubilee clip but this radiator appears to have some weird system and I can't for the life of me figure out how to remove the bottom hose from the radiator.

The attached photo is like the one I've got, there are some some notches around the outside of the pipe and the hose fits inside it rather than goes over it - I did think maybe there was some sort of c clip but I can't see or feel anything nor can I find any new c clips when Googling - I've tried Googling but it appears only the Berlingo uses this type of connection and all the other 2.0 HDi models use different radiators as the bottom hose is in the middle rather than at the side.

I've tried looking in the Haynes and that only goes on about bayonet type radiator hoses rather than whatever this type is called. Anyone have any experience with these type of fittings?

[cancunia]

Never changed one myself, but am guessing that bayonet means push & twist in this case?

Here's a fleabay item with a fairly good picture, not sure if it's top or bottom tho..
https://www.ebay.co.uk/itm/Gates-Radiato...0005.m1851