I would go to a local dealer(s) first and try some rifles out and see what feels comfortable. Then narrow it down to what you are going to be using it for......I.e if you are going to a local range / HFT then shot count may be factor for you, if its for hunting weight may be more of concern over count.
Once you have a list of ones you like then start looking for a package deal second hand. I would recomend using this site, the uk air rifle forum, the airgun bbs forum and also free ads. I have found these sites all have rifles coming up with loads of extras.......
Good luck!