What he said ^^^^^ but a little bit of extra information for you, the front ABS sensors on the 7/9xx range are the same as used on the front of Mk3 Cavaliers and the rear of Rover 800s but the plugs are different so would need changing to the Volvo plugs.
Also the only way you're likely to get them out is with a combination fo drilling, blowtorch, chisel and eventually die grinder.
Once they're out, lightly grind the hole so it's slightly bigger and polish to a mirror finish or as near as.
When you fit the replacement sensor, smear the body of it with a waterproof grease (not the tip) to help prevent corrosion in the bracket/control arm as this is usually what kills them - the corrosion forms crystals of rust which grow and crush the sensor.
If you're selling the car and just need to sort the ABS for the MoT to sell it, a cheap one will get you working again and the car sold, if you're keeping it, get the bosch one or a well-respected pattern part.
