I did the domestic / commercial crossover with Hybrid just last week & I can honestly say it's a good set-up.
As for you doing your ACS you need to be in a position to either work for nothing or even pay for the privilege. While I was at Hybrid last week they were fishing for me to take on a trainee to give them their 20ish hours experience but, as I explained I sub contract to British Gas & for me to take someone on I would have to pay for employee liability insurance & provide a CRB check as well ( money I don't have at the moment ), so that's where someone like yourself would have to pay to work but maybe someone else would be in a position to pay it.
As daunting as it sounds if you are able to do it then go for it, I did it 9 years ago & although it's not been plain sailing I don't regret doing it.
One thing I would say is get some experience with a firm for a few years before going self employed. I would have been fooked without the ability to ring round a few of the lads when I came unstuck, one thing I did realise is that after 2 years in college I knew dick all!
As I said if you want a chat & go through the full in's & out's give me a ring, my number is 07716 967311.