It would be a big ask to complete a C&G level 3 technical certificate if working full time. Not many colleges do part time evening courses these days. Day release may be the only way. If you are OK with an NVQ level 3 then there are many training providers in Midlands who will take you on their books. You will obviously need to clear with your employer as level 3 work based assessment is required to take place in the workplace. Where are you in the Midlands ? I may be able to point you in the right direction of a training provider.