So if it was at 1500 feet that's OK then although I'm not sure how you knew what the height was.
Can't blame the pilot for asking for a visual if they can see the airfield and are set up and briefed for a possible visual approach and can't blame ATC if they give him clearance if it is safe and expeditious to do so.
If it came in for a visual approach I have no issue with it being that close. If it was being vectored for an ILS approach, it is almost borderline on the guidelines of a minimum 4 mile approach. I used FR24 to note it's height when turning finals.
I am just curious to know how often you will find aircraft on a visual approach, that close to an airport on base leg.