Thank you Chrisbasset, just received the extra 15 GBP for shipping
Not sure about the torque spec from the factory: since the specs are now different, I would not take it for granted.
Do what you want but please listen to my warning: I don't want anyone here to lose a wheel! This is not my responsibility, use these at your own risk but common sense says that you have to triple check everything. I read so many things about spacers on so many car forums that I did make sure they were tight when I installed mine.
As far as I know, they are on my car and Isa's car for now, not sure what torque he used. For me, I torqued it without checking the value: just as hard as I could. And I checked twice: after a very short ride (300 feet) and after a 5/10 minutes drive. And just for good conscience, I checked it again a couple of weeks later. Since then the car has been driven on the road and on the track with no issues at all.