From your own Post you were Downwind following another aircraft and instead of following them as you are required to do (conform to the pattern formed by other aircraft) you turned Base where you thought you should due to 'Landmarks' and effectively cut in front of them.
A better option though would be to Go Around from Base Leg onto the Dead Side and join again. This also enables traffic behind to fly a "normal" pattern. Notwithstanding local noise rules any extending should be done upwind and not downwind.
Emergencies excepted, I believe an aircraft on Final has priority over all other aircraft and that for Straight Ins this Rule trumps the need to conform to Circuit Traffic - not least because they are not intending to join the Circuit Pattern.
Level Attitude, sorry beg to disagree with you here! An aircraft flying a straight in is not conforming with the pattern formed by other aircraft.
Good airmanship does dictate that at uncontrolled airfields good position reporting is required
As is also keeping a good lookout - even now there are some airfields which are non radio as are some a/c. Exceptional I agree these days with Unicom (or whatever UK call it) but still possible.