Firstly I would like to receive up to date stats and figures relating
to the rate of bank branch closures within the UK.

Secondly, what has happened to the properties after the bank has moved
out, any trends?

Thirdly, how have they been disposed of, sale and leaseback? Change of
use?

And finally any yields or estimated  rental values realised during
sale or valuation would be very useful.

Any of the above information would be very useful, obviously I will be
very grateful for any help you can offer!

According to http://www.debt-on-our-doorstep.com/html/briefing_5.html,
there were 4,000 high  street closures during the 10 years up to the
year 2000, with a further 1,000 anticipated over the next five years. 
Most of these were in poor or rural areas.

You will be hard pressed to get further data on the buildings via the
Net.

The most common re-use for "traditional" (ie the old purpose-built)
bank buildings seems to be as bars or pubs.

Owain