So I tried to search for ‘coil spring rubber insulator 115mm’ but was getting poor results (hits) on ebay or horrendously expensive.
The FB query in the livetodai group returned some excellent advice and websites;
From Malaysia a similar part could be found at 30-55mm thickness at very reasonable pricing:
https://www.on9carparts.com/goods.php?id=5737
https://www.on9carparts.com/goods.php?id=5738
Other sources also offered more specific parts at reasonable pricing;
The best part about the amayama.com is the technical drawing with the part numbers listed allowing for other parts to also be isolated (lower/upper seats and rear spring bumper). I have sent them a query to get a pricing on the lot as I feel I have spent all that money on the suspension but completely overlooked the ‘more’ perishable rubber.