Hello and welcome from a fellow UK-er!
As everybody has said - it is probably just time - so much change for the little mite, but congratulations on your new baby!!!
I personally would try to get him off Pedigree - it's not the best of foods
Wet-food wise, are you able to get hold of Lily's Kitchen or something similar? It's organic, holistic and apparently suitable for human consumption (if you care to try it?!!?
).
Dry food - again, opinions will vary greatly. All I know is, our Harry won't touch
anything but Royal Canin breed specific - it's very difficult for us to get hold of many of the varieties our friends in the USA recommend
Good luck to you both - I'm sure things will calm down soon
Sally + Harry
x