Still no joy on this problem.
I have found that UDMA66 was not enabled on my machine, and have since enabled it. Drive access times seem to have improved, especially in directories with a very large number of files. I have also checked the IDE controller settings and BIOS settings to ensure they are set to utilise UDMA.
I am now confused as to wether or not the Pioneer A05/DVR105 supports burnproof or not. Using RecordNowMax the burnproof option should appear under Tools > Options > General if, and only if, the currently selected drive supports burnproof. I see no such option which would indicate according to Stomp that the drive isn't burnproof.
However, having looked at the supported drive list for Nero
http://www.nero.com/en/content2/recorderP.html it lists the A05 as being burnproof when using Nero.
Also, RecordNowMax allows me to enable overburn. Whereas Nero's webiste indicates that overburn is not possible. WTF???
My next plan of action will be to install Nero and see what happens for myself.
If anyone has any further sugesstions of config changes to try I'd welcome them.