Huh… I think(?) I understand your base schema a little bit better now.
To get the desired result, you will need to adjust how you are thinking about your base schema.
Here’s how you get your desired result:
In order for the linked field to return “London 123” when you search using the linked field, the primary field of Table A needs to contain the value you want to display.
Here’s an example:

…and here is Table B:

Now, since the primary field of Table A now contains “London 123” (and other example values), when you search for “London 123” in the linked field values, you will get those results back with the numbers included.

Why Is This The Case?
The value displayed in the linked field is always going to be the primary field value from the record that is linked. Per your screenshot, it appears that Table A currently has the Location formula field as the primary field.
So, you would have to move the formula field and replace it with the Property ID field in order for you to replicate what’s in my screenshots.
Thank you. I did wonder if that might be the solution. i have other linked fields on this table and on another base without any issue but I hadn’t realised that the data in those was linked to the primary field value.
To achieve what i want to do is going to require a rethink of how I want to display the data.