I was wondering if there are any differences between the A12 and A14 cams?
At the moment there is a lumpy cam in the A14 but we have a standard A12 cam that we are thinking of putting in but we are unsure if they are different or not.
Otherwise we may have to look for a standard A14 cam.

Yes they are different. Look at where your dizzys(distributors) are in each motor

Are the lobes the same size on both cams?

There are different lobes even on different A14 engines. To know, you'd have to tell us the year, car model, market/region, and trim level for both engines.

Remember, A12 and A14 are the same (more or less) year for year. In other words, a 1976 A12 and 1976 A14 use the same kind of camshaft.

The change came in 1974. Starting in 1974, A12s have the distributor toward the back (same as with A14). Before 1974, it was in the front.

If the A12 cam has two drive gears on it, then it will swap straight into the A15.
If it has only one gear at the front, then it is an A10 or 1200 cam & you will have no drive for the distributor, so it's not really useable.

Different size A series engines, in different model cars & commercials will have interchangeable cams, but the lift & cam timing will vary from a little to a fair bit in standard versions, so yes, a two gear A12 cam will fit & work, but it might not give the same level of performance as the original.