Flue liners.

[plasticpigeon]

Would people recommend a flue linder with a Victorian/Edwardian style register grate? it seems a goo idea to me. If this is done, how is the liner closed off fron the brick flue at the bottom? Would I need a closure plate of some sort?

 

[kreyszig]

I think you're after something like this (the gather unit):

http://www.topstak.co.uk/relining-old-chimneys/gathers-and-register-plates-for-relined-chimneys/

Obviously the above would be a right pain to install unless the register grate is not currently in situ. I wouldn't bother if it meant removing the fireplace.
My main concern with not being lined is CO leakage,especially if that could happen into a neighbouring property, which you can't check as easily. Otherwise, if it all checks out, why not keep it as is?

 

[plasticpigeon]

Thanks the gather is exactly the kind of thing I was looking for. I'm not sure how it is installed but I'm sure it can't be too difficult.

 

[Zebra]

That's the spirit!

 

[kreyszig]

I did see one in my travels which was admittedly for a gas flue liner, but it was much smaller than the gather I linked to, basically just a little larger than the flue itself. It was to be installed by shoving it up the flue, and gravity + the wedged shape of it held it in place. One way to do it!