Relocating to Valencia - pensioner, a few questions

Hi all,

I'm a retired NY state law enforcement officer, resident in England for the past 6 years.  I've got several passports, US, UK and Irish, so that aids in my movement.  Living her to be near children at the moment.

I was considering moving to Valencia, lovely town and a good fit as I am tired of the cold - and I also speak Spanish.

I'd be moving there under what I assume is my right for movement, as an EU citizen (Irish) and I understand that I'll need to register with the Spanish authorities so I'm tax resident etc.

I also gather that there is a dual-taxation agreement between the US (where my pension comes from) and Spain, but there is some business with claiming back the tax I've paid in one country etc... Was curious if the fact that my pension is deposited into my US account would make any difference? 

Obvs I would need an account in Spain to go about my  day-to-day activities, but I'd only transfer (like I"m doing now) what I need via Transferwise or the like.

Was also curious about the requirement for private health insurance for a fossil like myself, wasn't able to make heads or tails of the info I've seen on the Interwebs so far.  Can anyone explain it in simple terms? 

I would be moving to Valencia in a flat that I'm hoping to buy once this whole lockdown thing is lifted, but as I'm retired I don't plan on working.  I might consider investing in further properties, if time/finances allow...  I've read a bit on taxes relating to rental income and that seems pretty straightforward.

Also - if anyone can recommend a decent Irish estate agent in Valencia, that'd be super!

thanks,

Grampa Kev