Guessing the UK flywheel is the TTV, and the US import is the STS Machining wheel?
There's also the KL Racing alternative - use an ordinary flat 8 bolt flywheel, then use KL's 60-2 tone wheel attached to the crank pulley, together with their mounting brackets and Hall sensor. This setup takes the place of the RPM sensor at the rear of the engine.
Bracket = Art No: 01591
Quoting the KL Racing page:
Sensor Art No: 04215
You also have to buy this sensor mount for engine block B230: Art No. 01590
Belt wheels with bracket for trigger wheels just to screw everything together are here:
8V width of crankshaft drive: 00238
16V width of crankshaft drive: 00227
8v width with multi strap: 01477
16V width with multi strap: 01460
The associated trigger disc is linked under each belt pulley
[They] have made the brackets so that they are adjustable front / rear and in / out
Screws are not included
https://shop.klracing.se/bilder/artiklar/zoom/01591_3.jpg
https://shop.klracing.se/bilder/artiklar/zoom/01591_4.jpg
See URL https://translate.googleusercontent.com/translate_c?depth=1&rurl=translate.google.com&sl=sv&sp=nmt4&tl=en&u=https://shop.klracing.se/sv/artiklar/givarfaste-1.html&xid=17259,15700021,15700186,15700190,15700256,15700259,15700262,15700265,15700271,15700283&usg=ALkJrhgois-fDMrzFTplSBQeLvFXRr4gcw