Personally from my experience working for a company and working your arse off for a company make no difference, i have put 110% into my job and it goes unrecognised so i decided i should set up and work 110% for myself and reap the benefits.
My job has not lead to progression and has not given me the experience i want to be a domestic electrician. if anything it has hindered my career, at the time it was a means to complete my apprenticeship along with promises of further training and JIB rates. All of which might i add fell through. Although i work to high standard (and safely might i add) i am sure that i don't do things in the quickest way. By setting up on my own in this position my problem will be the amount of labour to charge and the amount of time it takes me to do a job. Both are factors which i have considered alot. But then i look at my current wage and sacrificing the amount i will charge per day/hour to compete with other faster electricians is a hit i am more than willing to take.
I only meant to offer advice as i feel i am in a similar situation to the OP and have been for a couple of years. Maybe sending out another 150 job applications might get him somewhere.
If working your arse off for a company works so well, it makes you wonder why people ever both setting up on their own.
And working your arse off for a company is most certainly NOT the only way you will gain the experience you need, i could be over dramatic and say its the most foolish thing i have ever read but that has already been done once in this thread.
(i rest my handbag)