First Tropical Fishtank

[daizeUK]

2 days later with the filter and heater being on, the water has turned a slight grey colour (I'm sure this a bacterial bloom from what I have read from different sites) My question is, does this mean that I started the tank cycle and once it has gone clear and the levels in the water are ok, I can add me neon tetra?

 
No - the bacteria you see in a bacterial bloom are not the right type of bacteria and they don't have anything to do with your cycle.  A bacterial bloom appears quickly and should clear up by itself.  The bacteria you need to cultivate in your filter grow much more slowly and aren't visible in the water column, they form a biofilm which attaches to surfaces and filter media.  These nitrifying bacteria require ammonia as a food source so they won't start growing unless you provide them with a source of ammonia - either bottled ammonia or a few fish flakes left to decay in the tank.  Once you add ammonia then the nitrifying bacteria can multiply and your cycle can start.