The accessory drive belt and ancillary drive belt should, according to the maintenance schedule, be changed at 84 months or 105k miles so mine are overdue in terms of time not mileage. (NOTE: this not the timing belts as TDV8 doesn't have any)

Just ordered both from Duckworths and not particularly expensive at around £50 for both.

Not sure how urgent this really is since I had a good look at them whilst changing the alternator recently and both seemed in good condition. (just occasionally can hear a bit of squealing when applying big steering input).

Anybody ever had a belt let go on a TDV6 or TDV8? Cant seem to recall anyone reporting a failure. 2008 MY Java Black TDV8 HSE

According to the book of lies, the TDV8 aux belts are "fitted for life" and only changed if wear showing/damaged. 2012 SDV6 - it's missing a couple of cylinders
2008 TDV8 - it was a labour of love and is much missed

They are a PITA to replace, my personal suggestion is to replace them when a new alternator is fitted, which is generally sooner than every 8 years anyway