Plumbing help. Replacing toilet flush system.

[Whatsnewpussyhat]

My toilet flush is broken. I know I can just twist the part off the base like a bayonet but I can't find a replacement that looks the same as mine for a straight swap.
Not sure if it's just that loo is old and parts are better now? What can I replace it with?
2nd pic is off B+Q help pages but they don't sell it.
@PigletJohn ?

easier replacing the whole thing tbh

I don't suppose you can see a makers mark on it?

If the works twists off on a bayonet fitting, you're right, it would be easiest to swap.

I'll have a look later for a website that specialises in such things.

brokenbog.com I think?

and try

shop.lunns.net/toilet-spares-2-c.asp

Thanks for reply. I've taken the whole thing out now. Make is Siamp I think. Only mark I could find.
Am I right in thinking I can replace the whole thing with any make as long as the scew in bottom bit is correct size?

It's ok, I've found a match now. Thanks.