Oh it's good you swapped ICT for FM coz ICT really is pretty useless in terms of skills/time/effort you put in. I'd say you're tempting fate with the remark in English, instead of resitting but I hope it goes to plan.
If you don't mind me asking, what exactly were your GCSEs because 'no A*s' isn't THAT bad at all! You're really putting your abilities down you know? Just don't do that in your interview
I'll be honest, unless for personal/medical reasons, I doubt they'll allow for extremely poor GCSEs. They don't count for much, but they do count for something. If you have an amazing PS and reference, I'm sure there will be leeway.
The work experience in a games company sounds amazing! Make sure you dedicate a good portion of your PS to it. Talk about what you did and what you learned from it. Loads of people say 'I programmed blah blah' but never what they learned from it (e.g. a new sorting algorithm). Also, it's good that you've dabbled in programming, say you learned to program a certain task, mention that.
This guide here is very idiot friendly (I like idiot friendly) and it teaches you lots of little 'games' that you can start programming so if you dedicated a bit of time before you sent off your PS, it's worth a mention.
http://inventwithpython.com/You can read the e-book free online and practice those little 'games' and stuff. If games is something you're interested in, it might be doing a bit of research into artificial intelligence and reading like news articles on it. You could also mention how interested you are in AI in your PS, which shows the areas of CS you're interested in.
Oh UCL is a good university too. Erm, you might want to look at UCL/Southampton and Bristol on an even scale coz they all have a standard AAA offer. Personally, Bristol won for me, for overall course and city life. Bristol was my insurance actually. Other universities you might want to check out are Bath, Exeter (anywhere in the West Country is good). I hear Manchester and Edinburgh are good too. What unis do you want to apply to anyway?
If you're looking for a good Russel Group uni with a low offer, try Nottingham, their offers go as low as BBC I believe.
If you need help with your PS, want me to review it, PM it to me, but I can't help you until the 20th of September I'm afraid as I'm away with no internet connection
Do make use of the TSR PS help section though, it's confidential and very credible!