Borage is what I was looking for Frenchie. Although there are others which are as attractive to bees eg. Lavender or Majoran they produce clusters of flowers whereas the Borage produces single ones. The rate of nectar replacement fluctuates throughout the day - being higher in the early morning and evening - but at peak time the replacement rate is around 2-3 minutes. Over 24 hours the highest production of nectar is found in the Viper's Bugloss (Echium Vulgare) (also a borage family plant) - which maintains its production constant throughout the whole day - technically this is probably the most bee friendly plant there is, though it is easier for bumble bees to feed from than for honey bees. There are other plants which are quicker but they are tropical and are polinated by humming birds. Over to you.