i'd guess unless theres some odd UK FRTO law they are the same.
Copy Traffic to me is "understand your advisory and will look" as in yep heard that... looking now.
Normally i reply 'Copy Traffic and Looking, ABC' if i can't see the A/C.
If i can see the traffic i will say 'Copied, Have the traffic, ABC' or 'Copied, Have traffic in sight, ABC'
Then there is no doubt.