Removing rear disc bolts

[old son]

A mate has got a GS1200 with a worn rear disc. The T40 bolts that hold it on are like cheese and semi recessed. This mate has rounded one and has asked how he can get it out. The disc is fitted to the hub so he cant take the wheel to his local engineering shop unless he can remove the hub. For this he will need an extractor!
Anybody have any ideas how he can remove the last bolt? I suggested warming the disc. Does it sound like that might work? He can't cut the head off because it is recessed and he can't tap the bolt round with a centre punch because its recessed.

[Kosmic Kartman]

Can you get an arc welding rod to it? If so hit it with that. The sudden heat usualy breaks loose any seized bolts. Or cut a hex key and weld that to the bolt.

[AdieR]

Pics would be handy if you have any.

Some heat on the bolt head will help soften the loctite on it, a key slightly bigger tapped into the bolt with a mallet might help, an impact driver can be useful too.

[robby boy]

By T40 bolt I am presuming it is a Torx bit, I have removed rounded ones of these in the past by chapping in a spline bit and using a bit of heat. It might be worth giving the bolt head a smack with a drift and a FBH.  mash

[Tmation]

Some heat and a bit of impact are your friend.