had a cage altered that was made for another make of car and needed to be altered for a different make of car?

we went to see a really fantastic sturdy cage for the boot of our estate and it is at most needing an 1' of the height and maybe 1 '- 2' from the length :-(
other than thats its perfect  :-D 
really sturdy and locks not a fold down type

if any1 has had this done any information would be appreciated
was it easiy enough to be done?
i take it i would need a blacksmithto do the altering?
what did you pay for it to be altered? (if you dont want to say on the board you can pm me :-D)

thanks for any help

Michelle & gang x