I have a question I hope you can answer - I’ve paid a

Good morning - I have a question I hope you can answer - I’ve paid a builder in excess of £40k fir works including fitting a new kitchen, digging a hole for a sunken swimming pool and also laying a large new patio- we have an issue with the patio in that some of the slabs are starting to come loose. On inspection it appears to me that although the builder has put down a hard sub base, he hasn’t put down a bed of sand on top of the sub base to lay the slabs
JA: Where are you? It matters because laws vary by location.
Customer: onto. In addition to this error, he appears to have used the ‘spot’ method for cement- I don’t think that this meets buildings regulations
JA: What steps have you taken so far?
Customer: we live in wales
JA: Is there anything else the Lawyer should know before I connect you? Rest assured that they'll be able to help you.
Customer: We did have a defect report drawn up, but the expert failed to notice this unbelievably