to be feeling a little "shoved out"

[nervousal]

OK - I know I am - but if I cant BU on MN where can I?

I've had a single office in work for 4 years - in corridor with my boss/GM etc. With changes in organisation I've just moved into a shared office at other end of building to allow a more senior manager to have my office. Now - I know I shouldn't be annoyed/upset at this - but I can't help feeling shoved out of the way

And now that I'm sharing an office I won't be bale to be on here...

Yes, you are.
You have been 'shoved out of the way', in a sense, but not in a personal way. It is simply organisational, a matter of seniority, not because you did something or they don't like you.
they probably want more senior staff together, or in the single offices as a reflection of their position within the company or something?
If you want your office back, nab his/her job!