Belt Shredded on AJP 4.2

[DeeGee]

Following some very rapid acceleration then back to 30-40mph, noticed flapping noise. Opened bonnet to see front drive belt shredded around its circumference to about 30% of its width from leading edge!

Limped home but wouldn't risk any further driving.

Any ideas if belt easily available (part number??) and is it DIY replaceable?

Any previous examples when a previously undamaged, un-perished belt decided to give up without notice? Is there need/ availability of an upgraded belt?