I use electronic signature, just ask client to sign either there and then or when cert is delivered, we also email some of the clients direct so they can keep an electronic record and print themselves as and when required, you can also print site survey forms so that you can take a paper copy with you and fill in as normal, I usually keep warning notices printed off and then issue as normal but also keep an electronic copy, you can add continuation pages which allow more information to be added, i.e. reasons you believe to be unsafe,what tests you have done to come to this conclusion etc. The service/maintenance is also very handy because it gives you a record to look back, what has happened to the equipment, is it becoming a liability too much being spent keeping an old boiler going. As you can see i like them!