The Maritime Coastguard Agency (MCA) of the British commonwealth will issue a Certificate of Equivalent Competency.
A USCG 500/1600 GRT Master is equivalent to a MCA Class IV.
You only need to take a business/law class and do an oral exam to receive a CEC ticket. That will give you 3000 ITC.
This is a loophole to allow USCG 500 grt masters to run 3000 ITC internationally on foreign vessels.