Can't help you with any good garage in Reading, although Horsham Developments (traders on here) arent too far away from you and they do Suspension setups, also they know the Zed.
On the prices you were quoted, they don't seem all that bad. Most garages charge £50-60 p/h labour and a good aligment can cost about £100.
Try giving Horsham a ring and see what they can do