Which is not what you said ! You specifically said a survey is legally required.
And the answers to the TA6 are :
Non known
Non known
Not known
Non known
which is exactly what you will get on your boat buyers details form.
Brokers are very careful in their advertising so they do not have to admit to any known problems and will typically say :
Boatshed
The particulars detailed herein are intended to give a fair description of the vessel but their accuracy cannot be guaranteed, these particulars are not a part of any contract or offer and are supplied on the understanding that all negotiations shall be through Boatshed Brokerages, who are acting as brokers for the vendor. The vendor is not selling in the course of a business unless otherwise stated. The prospective purchaser is strongly recommended to check the particulars and where appropriate, at his own expense, to employ qualified agents to carry out surveys, structural and/or mechanical & electrical.
ABNB
PLEASE NOTE: This is sales information and not a survey report; providing content details only. The specification in these pages is based on ABNB's visit to the boat and on information given by the owner. This is to help you decide whether to investigate the boat further, be it by surveyor or otherwise. The information here is given in good faith but no description, statement, promise of work to be done, or suggestion for future use, constitutes an offer. If the craft leaves the UK, any necessary VAT paid status may not be available.
If you are not happy with this, then only buy from a dealer, or broker who owns the boat and is not acting on behalf of the owner.
You will then get the full might of the law on your side - including a full money back guarantee.