I hope you are well.
I am pretty new to Tableau myself but would like to offer my insight into your problem.
As far as I know, it is not possible for you to generate a filled map due to the fact that each club is only limited to postcodes and not a city/region as a whole.
Your best option, in this case, would be to use a shape and size on the map to visualise how each club is performing. I have explained below.
The following process to create a visualisation that will allow you to see how each club is performing depending on which measurement you use. For example, dragging the win %age onto Size will show you the below view.
Here's what was done:
1) Split the club postcode into two parts and used only the first part (renamed to Pcode First Part) so that Tableau could locate it. For example E20 for West Ham United or N17 for Tottenham Hotspurs.
2) In sheet 1 I dragged 'Pcode first Part' into the 'Detail' part of the Marks card which brought up the map with the dots.
3) Changed chart type to circle
4) Dragged Team onto colour (I chose not to filter on this occasion)
5) Dragged Win% onto size
6) Changed the opacity and border within the 'colour' part of the Marks card
7) Increased the size on the 'Size' card
The bigger the circle = the higher the win ratio. For example, Swansea (bottom left) has a higher Win %age than Cardiff (also bottom left), so the size of the circle is bigger.
I have reattached the Tableau workbook for you too.
I hope this helps?
Football Club Map.twbx 87.9 KB