It is hard to say really, they may look more kindly on you, rather than an accountant, as they appear to have some ability to be a little flexible on the interpretation (as per that link to their manual). It is a bit of a long shot, so it may work out that the fee is wasted, but only you know if you feel that it would be worth it.Do you think that I might have more luck trying to sort this via an accountant? I know that it would cost me for the advice, but if it's more likely to be successful then it might end up saving me money in the long run.
That said, there are other aspects of dealing with this income that you may prefer an accountant to deal with, for example the R185's if needed. If you do go the accountant route, do be very careful who you choose. STEP accountants are specialised in this type of work, so would probably be much more helpful to you than the average High Street accountant who may rarely get to experience this type of work.
Finally, and very importantly, you need to think about all of the stress and worry that this is causing you - would you feel happier paying someone to take on some of that burden?