An 05 has a manual adjusting mechanism underneath the car.

I would try adjusting it. It is a pain though without a ramp. In an ideal world you would do the job on a ramp. This is because ideally the exhaust and heatshield require removing; not handy if both have corroded fixings. There is a way around it:

-Drop the exhaust from the hangers and support the weight (the flexi pipe up front cannot be bent much at all before it breaks). I would recommend to keep the exhaust as close to the car as possible.
-Drop the heatshield onto the exhaust
-Grab a deep fit 17mm socket and put it onto a 1/2" wobble bar or extension bar with a flexi joint (2 extension bars may be required).
-Adjust until you get 4-5 clicks at the handbrake.

Furthermore, it is worth mentioning a few more things. If the handbrake balance bar (where the adjust is) is not sitting level, the handbrake mechanism will never work right. It could be down to the wrong cables being used or a seized caliper.