Dave Austin just may still have his, try contacting him via the site.
Sorry have just looked this model up, it looks like the old HFM one and not the one Dave has, if it is then I just may be able to help you out, but please do remember that my one dates back to the early 90's so some things just may be different to your's, I sorry that I can not post any photos as my one has been modified so many time it now does not look any thing like it was at the start.
I take it it has an ABS hull - the blast tank fit into the coning tower and under the deck - the W/C has three hatches - and only the front dive planes work, how am I doing.
This how I laid out mine.
looking towards the bow on the right hand side of the w/c I put the pump - on the left I put the servo for the front planes this also worked the on-off-on switch for the pump - next was the battery - then the motors - to the right of the motors I put the rudder servo.
The blast tank as I said was fixed under the deck, the one thing that I did on mine was to put a vent pipe into the rear of the blast tank, I then run the pipe along the outside of the tank then back into the tank at its highest point, this helped the air to escape from the rear of the tank when you dived.
Hope that his is of some help