You should continue to use existing and established international registers such as ISRCTN registry, or ClinicalTrials.gov. For trials involving both the UK and the EU sites, a record in the EU Clinical Trials Register will exist. Registration should occur before the first participant is recruited and no later than six weeks after recruitment of the first participant.
You should publish your summary results within these timeframes in the public register (or registers) where you have registered your clinical trial. You do not need to submit this clinical trial summary report to the MHRA as well. If your clinical trial is not on a public register, summary results should be submitted to the MHRA.