rookie wrote:
Well, I've spoken with the fitter and although he admits that the
joint is chipped he isn't prepared to do anything at all about it

call his bluff, take it to the small claims court:

https://www.moneyclaim.gov.uk/csmco2/index.jsp

/any/ reasonable man (or woman) would see that the labour
was substandard and not due to poor matriel and I'm sure that
everyone in this NG would support your claim.