Butano/Propano GAS wall mounted boilers

 Could someone please advise on a RELIABLE make of boiler, after 10 yrs and 4 replacements, I am faced with yet another change.

Despite the filtered, de calcified water supply all seem to breakdown, they never seem repairable, or parts cannot be bought!  And labour installation costs can be as much as half the boiler cost!!!!

Is it normal to have these SUB STANDARD models in MED countries?

I think you have been unlucky or been taken for a ride by the plumber.

I had the same gas water heater in a property for over 10 years, then I moved.  No problems during that time.

 My son has two apartments.

I fitted a new heater 10 years ago in one of them  (the pilot lights on water demand,  a very big saving which surprised me ) and the other apartment has been owned by him for 8 years, still with same water heater and no problems.

I second Johns answer, had these and never a problem, last one looked like a dirt cheap model, no whistles and bells and I know for a fact  it might have been at least 14 years old, perhaps that's the answer, get a cheap one with just the minimum controls so less to go wrong.

Couldn't even say it was over heavy on bottled gas, most of the time about  3/4 weeks a bottle maybe longer, sometimes it went so long it caught me out and it ran out.

If your so called plumber was a British expat he was probably milk man back in the U.K I am a gas safe engineer and from what I have seen over in Spain all you have is cowboys installing gas equipment the multi point water heater you are referring to can be repaired by a competent engineer the parts are widely available on the web but it would be easier for someone that does not know how to repair the appliance to just to fit a new one. 

I have no idea what is wrong with your boiler or why it is giving you so many problems, but I know what you are going through. I once had a dodgy boiler and eventually had to chuck it out and have it replaced. I didn't mess around and went for one i knew would last for years and years, one of the best brands is JUNKERS in my opinon. Never had a problem. Touch wood.