I'd guess that Gt-Grandad may well have been in the 1st Bn but was posted to 3rd Bn when it was formed.
We've established in Kennedi's album that one picture of him was taken in 1943 when 3IG were part of 33 Gds Bde.
http://www.ww2talk.com/forum/album.p...&pictureid=360
See comments below the picture.