Can the surveyors hold the money?
The short answer is no but some explanation is warranted.
Holding security is “Money Remittance”, a regulated financial activity under the Payment Service Regulations, and anyone doing so must be registered with the Financial Conduct Authority (FCA) and supervised for anti-money laundering by FCA or HMRC. The exceptions of “occasional or very limited basis” and “ancillary to another business activity” do not apply to money remittance.
There is a misconception that the Royal Institution of Chartered Surveyors (RICS) as a Designated Professional Body (DPB) under the Financial Services and Markets Act 2000, can license members to issue e-money which could allow them to hold security. The RICS DPB scheme, however, is approved by HM Treasury solely to regulate general insurance distribution in the UK, and nothing else.
It is now very easy to check if someone is registered with a couple of clicks on the FCA Firm Checker service. Under the service category “Payments and e-money, for example, online wallets and money transfers” check that the firm has permission to “Transfer money for you without you holding an account”.
Be sure to check “What this firm can’t do” as some permissions do not allow firms to make payments without your consent which rather defeats the object of security for expenses!