MGmike

Mike Satur has one on clearance for £86.96 here
https://www.mikesatur.co.uk/MGF-and-MGTF-Stainless-Steel-Exhaust-Heat-Shield-by-Mike-Satur

You'll struggle to attach anything to the existing shield which is a fibre based item. I used some ali heatshield material from a scraped mini but any modern will have something usable if you want to keep the cost down.