Yes, the original will along with the ink signitures of the people who witnessed and signed it at the office where it was made will need to be produced. The Solicitor will normally store the original copy for free, and produce it when a copy of the Death certificate of the person whos will.it was is handed over to him. The probate office will not act on a photocopy alone.
There are a fair few schemes around that provide a proffesionally written will via a Solicitor in exchange for a small donation to a charity that have aranged to be part of this scheme. These wills have all the benefits of one written at full price by a Solicitor, and are fully approved by the Law Society. My Daughter made hers through the McMillan Scheme, My Son in Law used a Scheme set up by the local Air Ambulance Charity. Both wills are stored by the Solictor that made them, saving any worries should a security box at home get lost or stollen. The Solicitor not also registers a copy of the Will with the office of the Law Society. The donation needed to enter this scheme is around £50 to £100, but you an include a larger legacy in your will if you so wish.