Although I’m not entirely certain I think that this lovely flowering shrub is a Knobthorn Acacia (Acacia nigricans). It is currently flowering near to Lazenby House behind Hope Hall at the University of Exeter.
A Dartmoor blog
The views and photographs of Adrian Colston
A Dartmoor blog 
A bit puzzling. Acacia nigricans is a Western Australian Wattle, I think, and senegalia nigrescens is a West African savannah tree, around 50 feet in height, and called Knobthorn Acacia – but I am probably wrong. I’m not at all familiar with these. It is certainly a beautiful shrub.
That is exactly why I said ‘I think it is’ – I’m still confused about the species – could be Mimosa Acacia baileyana?
I think that is probably much nearer – I found a pic of Acacia Le Gaulois Astier – an evergreen February flowering mimosa up to 5 metres with leaves that look very similar to yours, needing shelter in the hardest weather.. Suggest you count seeds later in the year. Was it attracting insects? I’d love to have that colour in my garden (sorry – jungle) at this time of year!