Hi.
I installed a witter stowbar detachable tow-bar on my XC70 but you can get fixed ones as well from witter.
with regards fitting this video of an install on a 2004 will be the same as your 2005, although he is fitting a USA style tow-bar the UK style would mount to the same points on the car.
https://www.youtube.com/watch?v=TPk6fDPMUMQ