Unfair by the E U

The  reason is simple. By voting for brexit you embarrassed the E.U on the world stage. They are just retaliating by kicking you guys in the Goolies. 

Vote to become a third country, get dealt with as a citizen of a third country. Thank goodness the people who voted for Brexit knew what they were voting for 

The only difference in rules between UK and Spain is that Spanish can stay in UK  180/360 (in one trip or over multiple total cumulative stays in a year)  and UK residents can only stay 90/180 (but can do this twice a year, which equals 180 days in a year).

Owning property has no relevance to these rules.

https://www.davidsonmorris.com/is-there-a-uk-visitor-visa-180-days-rule/#elementor-toc__heading-anchor-2

From your post, you state that you own a property worth €3 million (which cost over £3000,000.00   is this a misprint?), so why did you not get the Golden Visa?

Last year, before Orihuela Costa were required to increase the waste charge, my council tax in Spain was roughly 4 times lower than the UK. (I rent out a property in the UK which was my PPR and as part of the agreement, I continue to pay the council tax). I also know what my council tax is in a number of other properties because as and when these properties become vacant I, as the landlord, become responsible for the council tax during the void period. 

So it wasn't 10 times, or 20 times. But feel free to propagate nonsense. Although, clearly it will depend on the class of property you own in the UK and the property you own in Spain. The decision of certain UK councils to impose a multiple of council tax on 2nd homes is not relevant as that is simple to avoid through appropriate corporate structures.

The differential has decreased further this year because the increase in Spain with the removal of the waste subsidy together with inflationary increases is higher than that seen in (most parts of) the UK. 

To the OP, it's not clear what they actually spent on the property given where the commas are etc, but if you'd spent 3million Euros, I'd have thought you'd have gone for the golden visa which is a visa which gives much more freedom (and is why the EU don't like it if anything because it's likely been used disproportionately by Russian nationals whether in Spain or elsewhere where similar versions exist).

UK  voted  to  leave  EU,  some said too  much  red  tape, EU  did not  vote  UK  out, Your  problems  are in  your home  country, 

3 million  villa in  La Marina,   well  done

It's a misconception that the UK allows stays of 180 days in 360. It allows visits of up to 6 months maximum. There is no stipulation that a visitor has to wait for 180 days before returning. 

https://www.gov.uk/standard-visitor

Rgds,

Aitch.

Don't forget the Dover lads who it appears can stay as long as they like.

According to a quick Google, Rutland has the most expensive council tax in the UK. at £2,543 for a Band D property.

When I go on Rightmove and search on Rutland, I scrolled into the middle pages of those that were returned and it appears - except where they are new builds (or conversions) both of which will end up in higher bands than older properties, properties valued at £450k are still showing at Band D. Some £400k properties show as Band C whereas others seem to go into Band E or Band F where they're new builds/conversions.

So it's clearly not comparing apples with apples as the capital deployed to buy a property in Spain is almost invariably going to be significantly less than the equivalent UK basis. Re-aligning for that, I suspect you get much closer alignment between rates of "council tax".

As to which represents best value for money, I suspect we would both agree that one gets "more bang for you buck" from a council tax perspective in Spain compared to the UK - even if there's the same things to moan at in both like bin collections, pot holes and general cleanliness etc!

Forget all the pro rata palaver.  Bottom line is how much money goes out of your bank account.