labbadabba
Pattern Altitude
I usually just wait until I'm on the inbound final course and start announcing distance.
"BS6969 is on a six mile final for RY23"
"BS6969 is on a five mile final for RY23"
"BS6969 is on a four mile final for RY23"
yadda yadda yadda
Yep, I'll usually at some point reference that I'm inbound on the localizer approach, straight in RWY23. That way the VFR guys know that I'm at least on an approach and not just being a weenus entering the pattern on a long final.