It is a long established principle that we eat in order to live not in order to work. In order to claim meal allowance whether employed or self employed it has to be shown that you are outside your normal work routine. The BIM manual, having denied relief by virtue of the decision in Caillebotte y Quinn, goes on to say that in the case if an itinerant worker there could be a claim. From the limited information available I do not think that you fall into that category and I agree with taxattack.The point of principle in C v Quinn was that due to the strenuous nature of the work his appetite was greater than it would have been. The case where an allowance may be due is where you visit, say, a strange place, somehere out of the normal routine and as a result you spend more than would otherwise have been the case. You cannot claim just because you were somewhere else - and you cannot claim if, say, you take sandwiches from home.
As regards an allowance of Â£8 - this is a fallacy. Strictly you must produce evidence on each occasion that you are somewhere out of the "ordinary" in order to support the claim and th claim is for the amount spent. Whether an individual HMRC officer is preared to accept a round figure is up to that individual officer.
HMRC have rates that it will pay to its own employees where they are visiting a workplace outside of their normal duties and as a result they spend more than would otherwise have been the case. This is an agreement that HMRC as employer has with HMRC as government department. HMRC employees on claiming the allowance (which is Â£4.25 for one meal - national rate) have to sign a statement that they were away from their normal place of employment and spent more that would otherwise have been the case - false claims could, and have, resulted in dismissal.
The figure of Â£8 is probably an allowance than an employer has negotiated with HMRC to pay to its employees under circumstances similar to those outlined - it has to be auditable - but it does not apply to the self employed. An Inspector of Taxes may accept a reasonable figure without questioning, a lot of the time it depends how mauch tax is at stake, but you will have to demonstrate that an allowance is due and will probably be told to keep evidence for the future.
I hope this background has been of assistance - bottom line - from the information supplied it looks as though you are working to a normal routine and as such I agree with taxattack that the claim will be denied by virtue of Caillebotte v Quinn.
Internet Taxation Ltd