Jahn - See ... blue, green, yellow, red - interchange to your heart's content.
There isn't a unique solution. It's a duff grid.

No unique solution, 2 of the rainbow colours can fit in the snooker ball group and vice versa.

They're just red herrings Rossco - like on the programme.

I mean.

It's kinda crap.

FFS - will you use what little common sense you've been given. Of course it is!

Oh do you know what? I've just done this puzzle and it doesn't have a unique solution. Who's have thought?

*Who'd*

Excluding severe leaning needs, the only explanation is an old fashioned piss-take after all.

Oops,learning needs!ihave them too?

Now you’re just taking the piss 🤣

Not a piss take - just easier to show rather than tell :-)

Nice one BinDipper.
Simple* way to explain- if a clue can travel from group A to group B but not be replaced from B back to A, it is a red herring and fine. If a clue can swap from A to B and another back from B to A, so that the two interchange, that is not a unique solution and the grid is invalid. In other words, travelling in one direction is ok, but not back again. Easiest way is to cycle the crossovers eg. A goes to B but not back, similarly B to C, C to D and D to A
*(Well, a way to explain, anyway!)
I have made a non unique grid myself recently- it is an easy mistake to make, usually due to last minute changes that aren't thought through, but once you know the mechanisms you can at least try to avoid them (doesn't always work!) Best of luck XX

I'm assuming the answer given to the last group is not a comment but a reference to snooker?

ferguspuskas- it's a secret cryptic message- famous 5 presidents rainbow balls?

Cheers!

Shockingly bad, shame on you

It's hilarious that this one got so many comments- just proves that people don't actually read things through! ;)

Hey! I don't think this one has a uniq... wait.... never mind.

Lorna - huh???