hokiefyd 

I'd say it's a definite maybe.

The cassette itself will be fine. As others have noted, shifting may be degraded some due to shift ramp discrepancies, but this is not a big deal.

I think what you need to watch out for is upper pulley (jockey wheel) clearance on the 21t and 24t sprockets. Those are much larger than intended for their positions (2nd and 3rd, counting from the smallest/outboard), and most derailers are designed to pivot that jockey wheel up as the cage extends rearward to keep the chain close to the sprockets for clean shifting. With those sprockets much larger than intended in those positions, you may have a hard time maintaining clearance between your jockey wheel and sprockets. You may need something like a road link (derailer extender hanger) to physically move the derailer downward for clearance here.

Edit: I missed the response from rccardr above...my post is a strong second to that first advice you received!