Repair it if you can... Follow this link...
http://www.countyconchem.co.uk/OLDSITE/index.html#Nelson
...and navigate to:
"Saving A Victorian Bay Window On A Grade II Listed Building"
and
"TYPICAL 1930's BAY WINDOWED SEMI-DETACHED HOUSE"
The stuff is a bit expensive but far cheaper than installing replacements. I spent about £300 restoring all the cills and windows (36 lights with 12 opening) on the front of my 1930s semi and saved thousands.
Peccavi
December 2008