I believe that the uk caa will issue a licence verification letter to the employer on request together with the necessary fee. There is a form for this.
5 second google search shows the form to be SRG 1160.
The agency or new employer will need to email the caa to request the letter after you have sent the payment and the fee. So I sugest you contact your prospective employer or agency to confirm acceptability.
Last edited by PT6Driver; 16th Mar 2017 at 10:36.
Reason: dding form details.