I followed Tony's post on the UKGTL forum to get here. Welcome back to GTL Peter.
I have very recently purchased a T300RS wheel to replace an ageing Logitech G25 that finally cried "enough" , so perhaps I can offer some info, and maybe perhaps you can help me with a few setup/calibration gremlins?? My wheel and pedals are also on a full rig so we are in a similar situation.
The plug to which I think you refer connects the 2 pedal setup into the rear of the steering wheel housing? and from there the whole unit is plugged ( with a second cable ) into a USB socket on your PC? ( eventually
)
I can confirm that my plug from the pedals also feels a little "soft" when pressed into its socket in the base of the wheel, with no positive "click" which I would have expected. I cannot say that I have expended a huge amount of energy in trying to force that plug to positively locate, but thus far it has shown no tendency to fall out even in heavy combat.
If your plug feels too loose and you are genuinely concerned that you might be disconnected from your pedals mid race ( not an ideal scenario
) I would suggest that some strips of Gaffer tape to secure the cable to the underside of the wheel housing or to immobilise/clamp the cable with cable ties through a pair of holes in your rig's wheel mounting plate?
From my side of things I will be interested to hear how you set up and use the Thrustmaster software and especially the Force Feedback within GTL. I have some random gremlins with my wheel where I have no FF during practice and quali, but when we go to the grid I suddenly have all the FF working at maximum. At other times the FF is conspicuous by it's total absence in any of the phases.