None that I am aware off.
Many years ago, while working in one of the Big 4 accounting firms, it was agreed with the Revenue that a major multinational could expense every item under £3,000 (that is how long ago it was) as this was their accounting policy in the U.S.
It took a massive amount of work to get the matter agreed, the expense was written off over two years and the capital allowances at the time were granted over a shorter time than they are now.
As with yourself I'd be interested to know if there is any practice in this area for small expenditure.