You’re right, the MX5 parts I.L header shows 2 ports on the manifold, I guess I got confused with the racing beat option as it was my original choice but then VAT and postage kicked in! You just saved me £70 (which is what the shop was going to charge to weld on a bung)
I was also under the impression the sensor would throw a code because it’s measuring the same exhaust gases, I.E it’s no cleaner on the 2nd sensor as there’s no cat there so the emissions will be exactly the same.
I was going to spray it with VHT paint, do it black so it looked more OEM, standard for the MOT.
Did the other original sensor have enough wire to reach?
Mine will be the same as yours then, I.L 4-1, OEM Mid with Cobalt.
Will be the first time I have splashed out on car stuff other than general servicing for probably 5 years.