Who regulates estate agents?

[sparklybook]

If I suspected an estate agent of knowingly doing wrong who would I contact ?

From gov.uk

You must sign a legally binding contract with an estate agent if you use one to sell your home.

You must stick to the terms of the contract or you could be taken to court.

Estate agents must also treat buyers fairly. They must show any offers promptly and in writing to the person selling the house.

Estate agents are also legally obliged to pass on any other offers for the property right up to when contracts are exchanged.

Complain about an estate agent
You must complain to the estate agent first and give them a fair chance to sort out your complaint. If they don’t, you can complain to one of the following schemes:
The Property Ombudsman
Property Redress Scheme

If they belong to the National Association of Estate Agents www.naea.co.uk or the Association of Residential Lettings Agents www.arla.co.uk you can take your case to them, assuming you've had no joy with the agent.

It’s just I want to clarify some unusual activity locally

What sort of unusual activity?

Non standard construction houses that you can’t get a mortgage for being sold as a different type of house to clearly get around this
Suddenly loads all in one very small area

Have you checked the planning section on your local council's website? Surely 'non-standard construction' is down to the builders/developers?

Rather than the EAs, I mean? You need to revert back to the council surely?

Wouldn't that show up on a survey which you need to obtain a mortgage and I would choose to get one too, even if I was a cash buyer?