Very tricky with so many crossovers. A great challenge!

Possibly the best, very clever, very difficult. Well done.

2 of the answers in the 'egg' group can be interchanged with 2 of the answers in the 'out' group

Head and Man can be swapped over in their groups too. Not good

Psmith and Ajay - that was deliberate and I thought I was being a genius. Is it against the rules?!

Red herrings are ok, encouraged even, but you need to make sure two answers can't simply be swapped between the groups they are in and the groups still work. For example old head/tin head and old man/tin man. It doesn't matter which group you put them in as the groups still work. There should only be one correct final answer for the grid.

I have never understood this Psmith. Thankyou for explanation, but I am still puzzled.

Sorry Knockers but Psmith is right . There can only be one (unique) solution since the format only permits one solution to be marked correct and it would make a nonsense of the game to mark a (second or third) workable solution as wrong.

Ok I've got my head my head around it now.