Just to add to my last post after a little research
The key point is that I don't think that your harrier was ever 3 sqn "B"
Useful site is the Gutersloh plane spotters guide.
http://www.sg-etuo.de/pdf
showing airframe used by 3 and 4 sqn. 1982 - 1992
This reinforces the info supplied by Jackonicko
1983 3 sqn
AG XV752 GR3 (ab Jan.) ab=arrive
where it remained until 1989
(Note the prefix A in AG denotes 3 sqn. 4 sqn did not require prefix as if it didn't have a A it must be 4 sqn.)
1989
G XV752 GR3 (bis 21.11.) bis=until
Left 3 to go to 4.
S XV752 GR3 (ab 21.11.)
You can see by the end of 1989 all Harrier GR3 have left 3sqn
A year later 752 leaves 4 sqn
S XV752 GR3 (bis 05.10.)
No sign of it ever returning to 3 Sqn.
Next evidence is a picture taken at Cosford 1995
BAE Systems Harrier GR3, 9075M, Royal Air Force
Shows xv752 as 3 sqn "B"
the same as it is still at Blechley
Gallery
But look closely the "B" is in the wrong position to high.
The squadron badge has a yellow border all around.
compare with other 3sqn aircraft yellow border top and bottom
Spotting Group Gütersloh - Der Flugplatz von 1937 bis heute | No3SquadronGR3
My theory is simply that xv752 was repainted while at Cosford and 3 sqn colours were applied as the easiest option. Which it is if you have the dragon stickers available.