The flowers are like Daphne Laureola, which has fragrant flowers at this time of year but the whole plant is poisonous, much like a lot of garden plants!

The sap is caustic so wear gloves and long sleeves if you prune it.
Poisonous isn't a problem unless you start eating it (though you'd need to keep pets away from the berries).

Daphne laureola flowers in February or March and is less than a metre tall, so unlikely to be that, although it might be related. Sorry, I can't suggest an ID.

Thanks for the replies but Landgirl100 is right it's definitely not Daphne Laureola. I'll try take a photo tomorrow of the whole tree to see if that helps.

I've been looking up pics similar to yours - could it be Osmanthus Burkwoodii. I know most of them flower in April but the weathers been all over the place and quite cold.