Ok, problem rectified.
Replaced rear Park assist speaker, located above headlining alongside rear passenger dome light (pop this out to access through the hole) with a used one for $40 off ebay.
https://www.ebay.com/itm/Jaguar-XJ8-...IAAOSwmcJdo6ll
Page 2 of this link shows some pics for the process by others.
https://talkford.com/community/topic...ocation/page-2
Thanks for all those who gave assistance. cheers
