So I can't burn my shredded tyres? Drat and darn it!!
Just an aside, there is a difference between woodburner and multi-fuel. Woodburners need a bed of ash, multi-fuel (as with open fires) need an airflow underneath e.g. a grate.
Hope you find one on freegle, there's never anything like it on my local (Brum and Tamworth) ones. There have been a few reasonably-priced ones on ebay recently, but it's like everything else, never one when you need it!!
Best of luck anyway!