Many thanks Geoff. I feel much more at ease now! Please find attached photos. The design can be found here:
http://www.geocities.com/adrian_mack/
I'm really pleased with the finish however, I did rush things a bit - the finish is contact vinyl and I didn't wait long enough for the filler to dry over the screws before covering the box - so I ended up with a few raises and dips. However, I found two layers of contact film made for a better finish, hiding some of the imperfections. Still, when it's sat in the corner it looks great from the listening position (keep having to remind myself to watch the move sometimes...).
I changed the design slightly and put an internal vertical brace in because the top was only 25mm think and I was worried about flexing. I also changed the dimensions slightly so I could use some offcuts from the timber suppliers rather than buy an entire sheet - saved about $100 Aust. Only problem was that I couldn't fit the radio control unit on the front however, I prefer it in the back because the sub looks cleaner from the front. I also don't know if I changed from the 'golden dimensions' (if the design even used those dimensions).
It's an excellent small sized box with punch.
Cheers