PS - Its not for profit, its all free - even for posting adverts on.
Just want to try to only get the good builders to get the work and stop
what happened to me happening to others.

Good enough idea as it would be in a many other areas too.

The only problem would be the abuse of your website. Dodgy builders
leaving themselves many good reports or someone with a grudge leaving a
decent tradesmen many bad reports. If you have a way of filtering the
fake reports then you're on to a winner, otherwise......