Got to agree with others. I'm only fitting boilers and fixing stuff because I have to. I studied chemical process engineering to masters,worked as a civil engineer with Jarvis then a project manager with Carillon and other civil companies..... Downturn started .... Went from running £275M development to having £275 in my bank... I worked for free for nearly 3 years. I didn't even get scrap! It's a ok job but if you know nothing it's going to be hard. Find a greedy small business man and offer your services. You will get abused. Don't listen to training places they just want your money and will tell u were to go when you still aren't earning after 3 years!
What is it that you are so attracted to working with gas? Do you have any dependants? If you are free British gas are looking for trainees, they are however a pants company and want you to give your life!
I might suggest that you look at alternative technology, solar thermal, bio mass, air and ground pumps.... Green deal is set to roll onto commercial systems in 2018 and there will be lots and lots of work as all landlords will need to have an a rated boiler by 2015 or its £5k fine and all business will have a similar system in-place in future. Also fuel costs going up so everyone going to want to save a Penny or two.
I would possibly also look at being able to do epc in the interim , green deal is daylight robbery but you could jump on band wagon for the Eco funding part, lots of people 2020 qualified but still short fall of epc staff. Talk to stroma for info.