There may be a Lambda sensor available that has a longer lead, but I do not know what car it would be for. The Rover systems NEED the correct specific genuine Bosch sensor. For what ever reason, I have had no luck with any other sensor, they all show up as not working!
A bit o/t , but I used a lambda sensor from a Peugeot 306 GTi-6 on my spi Mini (as had couple spare and part no. matched). Cut and connected the wires to the Mini plug and it worked fine with crypton machine confirming all ok.
Ive got a universal sensor made by mobiletron at the moment, shows on the diagnostic as working ok and only cost
£15. They even provide connectors to join to the rover plug.