I have just finished making the item in question using a combination of 1mm styrene sheet for the platforms and 1mm square section styrene for the support structure. This appeared to be suitable sizing of material for 1:72 scale.

It was a devil of a job and quite fragile until quite a lot of the structure was "welded" in place using liquid poly..

The platform was spaced at the required gap above the mast top using a jig which could be slid out of the assembly with a few of the supports in place and then the remainder of the supports were added. Having made a 1022 radar antenna (72 scale) soldered in 0.5mm brass wire, I can appreciate the problems associated with the type 23 platform support but I would be hesitant about putting brass so high up on the model (added to the weight of the four antennae already mounted lower down.

The plan is to have the radar rotating using a "doctored" servo driven by a single AA battery. This gives an appropriate rotational speed. The drive from the servo, up the inside of the mast to the radar will be by a 3mm diameter length of styrene rod. That rod passes through a number of platforms so the drilled hole in each one has to be accurately lined up with the ones above and below it to act as bearings for the drive rod.

David