Is changing patio doors a DIY job?

[mattman]

We have some fairly standard sliding patio doors that I'm looking to swap out for a 2nd set of UPVC french doors a friend has offered us. The sizes match so there shouldn't be an issue there, but wanted to know if its a DIY job to swap/replace or whether I need to get someone in?

I'm fairly handy with a drill and a saw so not a complete numpty, but as it has a security element of access to the house I equally don't fancy fudging it up!

[mattman]

thanks for the replies - will check out some local fitters first before i get the tools out