The Hospitalter

Hi I have been looking at some properties up for lease on right move and zooplar The ones I am interested in are mainly offices or shops and I would wish to change the building use to a bar/ restaurant I am quite confused about this new E class system now, but if I want to do a full change of use into a bar then how long should one expect for the applications to take place. And if I only wanted to do a part change from the shop/ office to a restaurant, then again how long should this take? Thanks