Well after reading through all the replies I think that I am down to two of all the models put forward.
Valiant looks a very good choice because 2 members on here, camelgas and gasman who are independent heating engineers so they must know what they are talking about.
Then there is .....
Poly's (Logic plus)... because the 7 yr warranty is very appealing to me , and also, for the company to give an extra 2 years more than any of others, means that they are very confident on the quality of there product to offer this.
I know that the majority of you said get a Worcester / Bosch as they have or had
a good name, because that was the one I was thinking of getting myself before getting some advice of RIBnet
but maybe most of you had had them fitted a few years back when they were good so I think that it would more prudent of me to take both of these heating engineers advice in not getting a new Worcester at this moment and time, unless that is.... some more heating engineers come on here backing Worcester up.