I wasn't actually selecting the horizontal tool and placing the dimension points vertically - I was placing them horizontal and similar for vertical but that said your suggestion to use the Parallel dimension tool is very helpful (don't know why I didn't realise this before). But, and sorry about this, I seem to have an issue when using this tool as well. It's great that it gives me the actual measurements but I can't aligned the measurement text sensibly, indeed the measurement text appears upside down - any thoughts on this?
Having read a few things I wonder if I've inadvertently done something with the Workplane eventhough this is a 2d package
Thanks for your help