I have read the news item on the BSPA site and it seems that Lambert is a guest for Musielak. Sheffield are 'monitoring' Tai's progress on Sunday and Lawson is standing by to guest. Drew Kemp stands in for Claus Vissing.
Admittedly though, the news item is badly written and is less than clear.
Sad news. A rarity in sport, a competitor that did not divide opinion. He was respected and admired by all.
I was lucky to see him throughout his long and illustrious career.
One of the great guys.
The first meeting I went to featured a guest rider. That was well over fifty years ago. Additionally, I would venture that in a hierarchical list of 'the banes of British speedway', guest riders would not feature highly. Just an opinion.