No offence but if your having to ask on the forum about anything else, then you shouldnt be putting it in a report, escpecially considering that the tiler appears to have had a report of his own done too and you dont know who did it or there qualifications.
If your called to court, which i would say is highley likley as there is a counter report to yours then your going to be asked every detail about what you put in your report and why it differs to the report the other person has produced. If you come across as being unsure because its not something youve picked up on yourself then your going to do more harm than good for the customer.
I would also reccommend that you take photographs of any defects you've highlighted in your report as memory aids for the court day and that you copy and paste the relevant BS extracts into your report as well so that its there infront of you as you go through your report infront of the judge. You want to have all the information that your going to present in front of you, without having to reffer to books or guides, the best way to do this is to copy and paste into your report.
Also on the day remember that although judges will probably have heard thousands of cases like this, there not tilers or builders, so photographs that you can show illustrating whats wrong really help to make your point. If you can convince the judge that you are more credible that the other sides 'expert' then you have 2/3rds of the battle won.
I would make the opening paragraph on your report along the lines of "I have worked as a domestic and commercial tiler for x years, i learnt the trade by working as an apprentice for x years / at x college...etc etc. I have completed X amount of installations including domestic bathrooms, kitchens, blah blah blah. In x years I have had X callbacks or failures. I have been called X times to asses and correct faulty installations. I have the following proffesional qualifications blah blah blah, basically setting out your history and why your qualified / able to provide the report in the first place. This will make you look very proffesional. Also the more information you give the less questions will be asked of you meaning there will be less chance of you being asked a question you dont know the answer to. If you start having to say "I dont know" your credibilty will drop rapidly. The builder or his solicitor will be trying to attack your credibilty because they know full well this is the easiest way to get the judge to side with them.
I hope thats helpfull.
