Thanks guys.

It took a long time to get the weight down to a decent level in CAD before I got anything cut- theres some large cutouts in the base to help bring the weight down. The overall size is 45x45x16cm so it's not massive- just slightly larger than the previous version.

The hole spacings I used were 20x29.5mm I used 6.5mm holes to allow for some tolerance. Worked perfectly for Heatwave.