vynehound you had a lucky escape there, that sort of behaviour used to be rife in Spain and unfortunately it's coming back, more mis-selling and pressure when in fact the market is over-saturated with properties for sale.
They used to say 'trust no-one' in Spain and indeed with agents you need to keep that thought in your mind all the time, if they say something which worries you take time out, you dictate not them, if it sounds too good to be true it most definitely is in Spain. Steer clear of the large agent groups with several flashy offices and their glossy magazines, you will pay for that.
Check what similar properties have sold for recently if any have, not 5 years ago, and knock off the 11-12% completion costs from the price at least, or better go in with a 20% reduction (to cover yourself) and say it's your final offer. There are 1000's more to choose from, someone will bite your hand off.
Or better still, invest in the UK market, and go there for as many holidays as you like without the unknowns.