g1smd - 10:40 pm on Feb 22, 2013 (gmt 0)
Why are you adding a redundant
.html suffix back on to the URL? You do not need it.
With several changes in URL format in the last few years you now need to proceed with extreme caution.
The first step is to document all of the various formats, all those with parameters and all those without.
You'll then need to set up single step redirects from all of the old formats to the new format. You need to be very sure that no request results in a multiple step redirection chain. Rule order is crucial.