Crankshaft Sensor Help please

[Jambo1uk]

hi i have a 2.0 passat estate 05year had a code pop up for the crankshaft sensor have got one got to the bit where i remove the thing
and it is solid i have tried a 4mm t bar and its a bit sloppy a 5mm wont go near it any ideas from anyone thats dont this please it is doing my head in and i dont want to round the thing completely (borrowed father inlaws long reach hex keys wobble end type had a ok grip but slipped at the last bite)
thinking of getting a new long reach no wobble see if that will help thanks in advance Jamie.