Occasional problem changing gear

[jeffco]

For a while now I seem to have a problem changing down gears if I have brought the bike to a stop without down changing as I slowed, when im stopped and I try to change down it will go down to about 3rd them wont go further without a bit of jiggling about. Other than that the gearbox is fine, no missed/ sticky  gears  and changes down fine if I change down as im slowing. Is this a common problem? or are dark clouds forming on my horizon ?  You can tell that ive just had a week in Scotland , still looking for bloody dark clouds...