Laying plum slate over blue slate!!

[youvegottobekidding]

So I have some blue slate running along just about a metre wide & 2 metres long in the back garden. It's only a thin layering. We've decided we want plum slate there instead, so instead of the ball ache if shifting the blue slate, DH suggested laying the plum slate on top of the blue slate, but I'm not entirely convinced it'll work, i reckon it'll get mixed around & look crap eventually. Are we better off shifting the blue slate first & doing it properly?

I'd shift it to be honest.

It will be more of a ball ache trying to pick out all blue once its mixed