As part of validation for an upgrade from postgres 9.1 -> 9.3 the client wants in the testing environment a comparison of the database before and after so after importing the data from one server to another and running the upgrade I have pg_dumped both the old and new databases in plain text format.

There is a complication that the old server is running in "GB" timezone and the new server is in "UTC" so pg_dump honours that so I can't just diff the output it as one dump switches between ":0" and ":1" on the timestamp whilst the other sticks on :0.
Is there an easy way to process the GB timezone dump file to modify any daylight savings time entries (ending :1) to UAT in sed or perl so I can do a like for like comparison?