Thanks for the comments guys .. really keeps me going on this now.
I've had a creative mental block
Last night I managed to get the bottom tray out of the case and start shifting the PSU into different positions, but it's hopeless .. the place and orientation it is already in suits it the best, so...
I'll wait for the cable to turn up this week and measure it so that the PSU is as low in the case as possible and then use the bracket I created above to cover the massive hole I am about to DREMEL into it.
for those who doubt my dremel addiction
the kill list so far :
DVD Drive bays sliders x 4
lower case tray
lowest drive bay removed
mid drive bay removed and butchered (decided to mount HDD with velcro)
hole in bottom case (not my finest moment)
140 + screws bolts, rivets and other fittings
Mr. Advent in several uncomfortable places
and I've even used the polishing tool to "File" some rough edges
Admittedly I haven't been the most creative with the dremel, I have only had one since starting this... and I'm not even slightly artistic, or experienced
I am loving the constructive criticism guys keep it coming, without it I'd have just thrown it all in the box and shut the lid
time to do some more cutting before this damn rain comes in, or the missus gets me to do laundry or something !