Insullation panels?

Halstead Quattro Gold boiler
Inside there is a heater box and inside this box is the element and insulation panels (feels like soft asbestos (but not asbestos) I think approx 8 x 6 or 6 x 6 inches.An engineer tried to fix boiler, One broke and fell onto heater element so boiler keeps switching off.
Question: What are these panels called and if boiler obsolete where can these be sourced from? Many thanks