You could try asking the unis you want to go to directly - some might take you if they feel you can cope, others will say a definite 'no' unless you go on an access course. Most access courses are not subject specific anyway, they cover general areas such as humanities, sciences, social sciences etc - what you learn most is 'how' to study, write essays, cope with the workload etc. My friend is currently doing one where he goes to college for a few hour three nights a week - maybe this is an option for you? Also, even if you can't take Japanese as part of the course, maybe the college will offer introductory or even GCSE level, which would be really helpful.
It's also cheaper to use a year to discover if uni is what you really want than waste two or three finding out that it isn't ... realistically, you will most likely be in debt at the end of three years, and one more isn't going to make a huge difference.
It's difficult - at the end of the day you should do what you feel is best for you. If you want to go straight to uni and think you can cope then do it! It will be a massive learning curve but it will be worthwile. On the other hand, the people I know who have done access courses and then come to uni have nothing but praise for them, they have all found them really helpful.