Insurance for apartment

For insurance I would recommend Right Move Insurance.

https://rightmoveinsurance.com/

A note of caution, if you are planning to let the property as a short term holiday let you will need a Tourist Licence, you will get more information on this in Davebev's Guides on the Forum, the authorities are clamming down on those who do not obtain the Licence with large fines for both owners and those renting.

Davebev1's guides: Renting out your property as a holiday let in Spain

Just taken out a policy with Intersure for an apartment a tiny bit larger in Villamartinalso got quotes from Mapre and Banc Sabadell. Intersure wasn’t the cheapest at around £230pa, but we believed offered the best service and value of cover. This was not for rental however, simply our own use.

is that minimum bathroom size for all properties i wonder?  The bathroom in my apartment is 200cm x 158cm .. which is nowhere near 4.5m2... that size would mean the bathroom would need to take up almost 1/2 the whole flat! :-)

You won't get a tourist licence with a bathroom that size. The best you could do would be to let it out either long term or as a seasonal let as there is no getting around the rules. This is a really hot subject here, booking sites cannot advertise your property without the licence and you risk huge fines if caught renting out without it, even to family and friends unless it is offered totally free of any charges for them. Your estate agent will absolutely know these rules and I hope you are not using the solicitor recommended by them as both will obviously benefit from the sale going through.
I can imagine the rest of the world will follow Spain in some form or another, sooner or later.

Thanks Cheryl. Disappointing as the agency (one of the biggest in the area) have been pushing for me to put the property under their wing to manage holiday lettings for me. Luckily I'm not buying for investment, but would have been nice to make a few bob during high summer when I'd probably not want to be in Spain... to help cover costs etc. But clearly not to be. 

You could still try to let it out over the winter months, plenty of people like to escape colder climes for a few months and others like to rent for a few months whilst looking for a property to buy as it is always a good idea to check out the area in winter because it can be so different from summer but this is probably only viable if the apartment has heating because it gets very chilly on winter nights.
A few tips if the property is likely to be left for extended periods; the traps can dry out leading to nasty smells, just run all the taps, showers, bidet etc for a while to refill them and flush them through. Humidity can be a problem, leading to mould on walls and furnishings so get yourself some humidifiers and leave some windows locked open if possible. Make sure you read the T&Cs of any insurance as some have a maximum number of days allowed for the property to be unoccupied. You may also want to think about getting a registered keyholder and let some of your neighbours know their contact details in case of any problems, especially the flat immediately below. Nicola (French Martini on here) of Fincas Inland has been recommended many times.
All the best with everything.

that's great advice - thank you.  

Try Intasure