Usually when the clocks change, I always end up having problems with my bg levels, mainly because I have a different basal rate running for every hour. So my midnight basal rate (old time) becomes my 11pm basal rate which on the old time was different to my midnight one. My body doesn't know about the time change, it only knows that I need a certain amount of insulin at the time that I need it.
The only real way of getting around it all is to do another basal rate test and adjust all the basal rates using the new time. I have cheated a bit and not done one as I am waiting for the weather to get much colder so for the time being I have just adjusted the time by 30mins on the pump as that hasn't affected me that much.