They're just straight re-issues with new packaging.

I have not been made aware of any difference in content in any of them.

Yes they tend to re-issue a lot of Playback stuff don't they?

Got my new Hi-De-Hi set today and have to say it is rather attractive. Nice and compact.

Apparently there is an extra few minutes in S01E02 that wasn't released previously. This just according to an Amazon reviewer - I have no idea if true or not.