Today I stripped the tank for the 2nd time. I found why I didnt get rid of them the 1st time, There were loads of them living in the filter foam. I put a few of the larve into a cup and experimented with various ideas to see what would kill them.
A soloution of 50/50 Bleach and water DIDNT kill them!!
A soloution of 50/50 Disinfetant and water DID kill them but I didnt want to use disinfectant with my tank
Boiling water worked straight away though.
I boiled everything from the tank, Obviously not the fish. I carefully washed the tank out with boiling water too, I know it was very risky but it didnt crack the tank. Now I need to add some mature media from one of my other tanks and refill. I will see how it goes.