I think it is about time this what put to bed as it seems to be going round in circles now.
Thank you to everybody who has posted, firstly I have learnt that it is not what somebody is willing to pay you that counts but what you are worth that is most important,
I have also learnt that there is a very slim chance of a plumber taking me on as 90% of plumbers are either looking for an apprentice or a cheap labourer and is only willing to pay the going rate for an apprentice.
I have also learnt that although the NVQ is a worldwide recognised certificate, it is not worth much to a plumber, experience and Gas safe registration is the most crucial recognition you can get.
Also I have realised that this business is a lot harder to get into then I first believed.
I still believe that £100 is a reasonable amount for a day and will not give up on this, but I am also going to keep my options open in regards to daily rates. (£50 a day is better then being self employed and getting nothing in a week.) If I get offered a job for £50 a day, then it might be worth considering, where as before I would of dismissed it straight away.
Finnaly I would like to say sorry to anybody i may have offended as this was not my intention, I was simply argueing the case, rather then not listening. Thank you to Everybody who has posted.