An alternative to having a helicoil put in, is to use ArmaCoil. The kits (that contain everything you need) cost between £20 and £40 depending on the specification. You can get these over the counter from any (UK based) Machine Mart, although they do have worldwide coverage so I guess they are available anywhere.

Armstrong Precision Components, APC, Armacoil Global Partners

These will alow you to repair the hole to the same spec as what it should be.

Helicoil kits
 

You need a 6mm helicoil kit (6mm diameter x 1mm pitch). There are many different brands (Helicoil is just one) they come with with the special tap, a tool to insert the coil, maybe a tool to snap the tang off and maybe a drill. If the kit does not have the drill you will need a 6.3mm or a 1/4" drill. The tool to snap the tang off is just a rod to push into the hole. You will also need to take the clutch cover off to do it properly so get a new gasket as the old one will prbably tear as you take it apart, and also have a tray ready to catch any oil that leaks out whan you take it apart (and some new oil to top it up when you finish).

Make sure you are square onto the hole when you drill the hole out and when you put the tap in.

Good luck, Dave

Noticed my top left bolt is threaded. Oil is only seeping at the moment, it will hopefully wait until i do an oil change.
I havent removed the bolt yet, as i dont want to have to repair it sooner than i have to. How long is the bolt? Not sure if it screws into the clutch cover, or goes right through into the crankcase.
If the bolt is short, and only screws into the clutch cover, surely it can be helicoiled with the clutch cover still on the bike?

The top two go through into the crank case, ie they also serve as clutch cover bolts. The bottom one only goes into the cover.

Dave