Georgian Flat - bring it back to life!

[ss82]

Hi, I am not sure if this is the right place, hopefully someone can point me in the right direction!
I own a lovely apartment in an ex-army officers mess. It was built in the early 1930's although everything about the building is Georgian. It is Grade II listed.
It was derelict up until 3 years ago when the MOD sold it and it was converted into 18 flats. We personally have the massive grand entrance, sweeping wooden staircase, huge long internal hall in our flat with incredibly high ceilings. Obviously anything that was there (original) is gone due to conversion or dis-repair. The windows, still massive, are sadly now double glazed but still 'sash cord' style, 18" Deep window sills.
Now, my question, I really would like to restore it back how it should be. I have a few ideas from my nans house (!!) but TBH hers is a bit of a mishmash as half is built 1630 and the rest 1804...! Where can I get pictures / book / website or anything to help me out? (skirting boards, cupboards, picture rails, ceiling rose all that kind of thing) The floor boards sadly are gone, apparently they fell through it was so rotten
Also, more on a knock the wall down thing I guess, we do have 3 chimney stacks hiding behind plasterboard, now which way the actual fire place faces I have no idea (our flat or next door!) would I be able to get some sort of plan from somewhere?
I really haven't a clue wher to begin, I just want to do this place justice and not live in a taylor-wimpey style home like everyone else I know!
Thank you for your time