On Saturday, 14 March 2015 12:00:31 UTC, nemo wrote:
We're told that we need to have our rental property inspected to comply
with H&SE requirements and that it will cost £81 every two years for the
privilege.

Who is telling you this?

A managing agent with a kickback arrangement with a friendly plumber, perhaps?

Here's what the H&SE advises:
http://www.hse.gov.uk/legionnaires/what-you-must-do.htm

Yes, if you have any cooling towers in your house and the H&SAWA applies.

The following will probably apply to some degree on the radiator circuit:

- the water temperature in all or some parts of the system is between 20-45 °C
- water is stored or re-circulated as part of your system
- there are sources of nutrients such as rust, sludge, scale, organic matter and biofilms
- the conditions are likely to encourage bacteria to multiply

Your risk assessment and action would be:

- use appropriate system cleaner/inhibitor on the primary circuit
- system is closed and any water loss / aerosolisation could normally only occur:
- when draining the system down
- when bleeding a radiator
- cover the bleed valve with a cloth to capture any water expressed

all of which you would do anyway.

If the managing agent is inspecting the property already then H&S should be part of that.

Owain