Yesterday i tested the theory. Flashed it to stock, booted to OS and skipped all the config disabled WI-FI and DATA so it couldn't pull updates. Tested Bluetooth and the issue is present. The Bluetooth did work correctly before i started rooting it. This is unlikely a hardware issue so can only assume its an issue in the build i have from Sammobile. If any of you have access to a stock pre-installed rom that works that they could give me access to, so i can do some testing or indeed any advice it would be very much appreciated.
Device = Samsung Galaxy Tab S4 (SM-T835 on EE)
PDA = T835XXU2ARJ3
CSC = T835OXM2ARJ3