I changed my name a couple of years ago after I got married -
You can order a new passport
upto 3 months before the ceremony which is post dated to the date of the ceremony but as the tickets are in your maiden name that doesn't matter...
Anyway - After you have been married all you will need is your marriage certificate (& your current passport) You can pick up a form from any postoffice or complete online & they will send it to you to sign & send back with the documents.
http://www.ips.gov.uk/passport/
My passport expired so I had to get a new one & change my name & go all the way up to london to stand in a queue to get the thing 3 days before my holiday it cost a fortune! But if you have an existing passport it should cost you about £70.
anyway - hope that helps xxx