Different vehicles generally have different lambda sensors as the number of wires/length of wires and connector plug can vary. The actual sensor part is usually the same.
"Universal" lambda sensors can be bought cheaply from any motor factors, around £40-£50. Universal ones are sold with bare ends and have either 1,2,3 or 4 wires.
All you need to know is how many wires yours has. Then chop the plug off the original, and connect it to the replacement sensor.
Cheap lambda sensors dont tend to last very long though. If you're opting for aftermarket and keeping the vehicle, go for NTK (part of the NGK group), Bosch or any other well-known make.