Yes, you must be referring to "Rastus", the red rat who allegedly lived under the platforms at King's Cross. He still exists somewhere in Roy's "shed".
Some shed, As someone once remarked, you could fit three of their bungalows in the same floor space!
Roy was certainly a prodigious modeller, and was always prepared to hep folk, and led by example when he said that you have to actually do something rather than just talk about it.
I will miss the camaraderie and friendship of many years.....life will not be quite the same without him.
RIP Roy.
Pete
(Tony just beat me too it about Rastus!)