Bed and Breakfast (Darts)?

I hear this all the time in the pub. When a dart player is aiming at 20 and slops a 5 and a 1 for 26 points: "bed and breakfast". Where did this come from?

Bed And Breakfast or Half-a-Crown or Murphy: A British term for the score of 26 in an 01 game, from hitting a 20 and one each of the adjacent numbers, 1 and 5. So called because breakfast used to cost 26 pence.
BREAKFAST: A score of single-5, single-20, single-1 in a game of x01. This was based on the typical price of a bed-and-breakfast, 26 pence.
Not a very convincing explanation! 26p is not very much; not even enough for breakfast on its own. Decimal currency was introduced in 1971. In old pence, it would be worth two shillings and two pence, 2/2, but would not be called 26 pence.
Search on Google for Dart Glossary for lots more terms.

Could it be derived from the half crown? Two shillings and six pence, usually abbreviated to '2 and 6.'

Two and six, 26. That's more like it!