I assume those shields are a springy scroll sort of construction that wraps snugly round the valve in question- I wonder if a bit of creativity with tin snips and food tins etc. would make a workable substitute?
As an aside, those pictures in the link seem to set a new reference level of gruesomeness in the "got at" stakes. I was feeling rather ill by time I'd got to the one with the bridge-too-far rectifiers, the extra (PCB-mount?) transformer secured by a tie-wrap and what appears to be a mains filter culled from an SMPSU, nicely insulated by a gash piece of cardboard! A feast of gaffer tape. I can well imagine that a single-ended audiophile amp with high-power triode and high-efficiency horn speaker would need an HT filter that included 2x 470uF smoothing but surely not a modest current HF radio?
