pre existing medical condition

It wouldn't necessarily be 'too late' to get private healthcare. 

You would need to take out private healthcare as part of the visa process if you are wanting to move full-time to Spain and would need to declare any pre-existing conditions. The issue would be that the premium is likely to be higher to take into account the pre-existing condition.

Quotes vary widely, so it's worth shopping around to compare prices.

I've just completed the Non Lucrative Visa process and moved to Spain full-time in May, so I hope this helps and I'm happy to answer any more questions that you may have...

Thanks RichT, thats something we will look into. Just seems like quite a few ducks to get in line still, but each duck gets us that bit closer.