Hi Lee,
021 905 377
knock sensor with wiring harness
500MM
white
Model data: ABV
Item 8 here: http://www.oemepc.com/vw/part_single/catalog/vw/markt/RDW/modell/COR/year/1995/drive_standart/76/hg_ug/906/subcategory/204000/part_id/3704672/lang/e#sec_9
Heritage have them listed at £26.40 each https://www.vwheritage.com/021905377-knock-sensor-for-vr6-vw-spare