I was just pottering around the garden and brushed past the mint to see a mass amount of them flying all around. I went straight on the internet and found this tip which is inexpensive and its something that every home has.
Apparently, you mix a small amount of mild washing up liquid with water and spray this on the leaves and as close to soil as possible. Fingers crossed this works !!
On a more positive note, whilst clearing the garden I discovered a large red gooseberry bush and some fennel, I had totally forgotten I planted them.
If you need to know more about pests and diseases for house plants and food produce, take a look at this link BBC gardening advice - pests and diseases.