Does anyone know of a bike shop that does left-hand crank re-threading work? If you do, do you know how much they charge?

I have a left-hand Stronglight crank with stripped threads. There are basically 3 methods of repair:

* Drill out, tap and Heli-coil (or http://ikekin.co.jp/contents/catalog/original/recoil/pricelist-pdf/pricelist.pdf"]Recoil)

* Drill out, tap and fit a https://www.winstanleysbikes.co.uk/product/40232/Cyclus_Replacement_Pedal_Bushes"]bush

* Weld up the hole and tap to 9/16-20.

I've had a right-hand thread Heli-coiled by a local engineering works (cost $60) as the size happens to be the same as a motorcycle spark plug but they don't have a left-handed tap or Helicoil. I would buy them but it seems only kits are available, with 5 X lh coils and 5 X rh coils at around $180 - a bit dear for a once off.

I've contacted 3 shops here in Tokyo but not only do they not do such work themselves, they don't know anyone who can either. I've telephoned 3 shops in the UK and it's the same story. Ideally, I would find someone in the UK as I have family there I could send the crank arm to. Failing that, I know a few people in the US.