Latest information on plugs is that the Beru units originally supplied with the first full conversion harness which McPhee got in late 2004 are standard VW plugs, and that a Bosch or NGK equivalent in platinum should do the trick. Conventional NGK B6HS (or is it ES?) work perfectly. (0608)

1965 VOLKSWAGEN BEETLE  1.2 H4 D 1 bbl
Standard B6HS gap 0.024
Iridium IX BR6HIX gap 0.024
 

Auto_Sparkplug_Adaptors

Limbach also do a harness for auto plugs - the plugs are three electrode type with Limbach brand, apparently. Speak with Nigel Baker about these - they are fully certified and can go on with only a log book entry.

See also G109 100 Hourly for REL37B information

Limbach External Oil Filter