I’ve given up on the idea of buying a ball point torx bit and have instead opted for installation procedure B, which involves, all by reaching down into a narrow slot:

Remove intercooler fan

Remove one end of intercooler hose

Loosen other end

Remove intercooler

Move loosened hose to one side

Unplug throttle body

Remove throttle body (having bought an E10 socket)

Unplug sensor

Attach T30 socket (having bought same) into the bolt securing the sensor which is now just accessible

Hope that the bolt comes off

Try to extract sensor and hope that it does so

Repeat all these in reverse.

Cost to date: one sensor (€30), one Torx socket set to include E10 and T30 sockets (€36 including postage)


Learnt today: there are such things as E Torx sockets