Wow thanks for the replies
I'm not dead sure on the cost but it came to about $200 in components if I remember correctly. (Locks, Hinges, sliders, gas struts etc.)
Then I used 2 sheets of 12mm Marine ply which were about $60 each I think. My school payed for 1 sheet and all the screws etc. so it reduced the price a bit.
The carpet was also marine stuff which was about $30 p/sqm and if memory serves me right I used about 2.
I still have to do the last bit of work on it to install the locks for the top and put the drawer striker plates in.
I still want to get some tie down points in the lid but cant find any I like.
Tassie your point on the front section might still be considered but for now the plan is to use that compartment for cans as its about the perfect height.