Stuart, what exactly is the hazard in these cases? Is it violence/lone working?

IMHO your guys need two things:
Some guidance/ training on how to deal with potentially violent situations eg knowing when to run away
Some sort of register or other way of sharing information/ reporting incidents so that your people know which properties are at risk and require extra precautions. I know someone will raise the data protection issue but it is permissible to hold such information if it is for the protection of your own workforce.

Stuart

Your question stated' In the past we have had instances of the customer suffering mental health problems. Does anyone have any guidance on how our engineers should deal with situations that may arise (and they have previously)'

On the basis of the information you provide, and the use of the extremely vague expression 'mental health issues;, there's a very serious risk of your company breaching The Equality Act 2010 through indirect discrimination and being sued for damages that in principle have no upper limit.

To control this risk, it's advisable to train all staff with customer contact in the company's responsibilities and liabilities in relation to customers about whom there is reliable evidence of a psychological impairment, relevant to the work of engineers visiting homes. For example, as a standard procedure (not limited to those with alleged 'mental health problems', without any reliable and valid diagnosis) to establish whether any problems of communication can present obstacles to effective service. In that way, you can construct a log of screening information to present in court in support of a valid and lawful basis for customer differentiation. In this respect, your staff are essentially no different to the challenges facing social workers, psychologists and psychiatrists obliged to make home visits although they can insist on police assistance in cases of evidence of risks of harm

Another thing to think about is sexual harassment etc.

Kieran,

Thanks for your advice.

Can you recommend any books on self awareness?

First of all - just so there is no hidden agenda - I make my linving as a professional pscyhologist (but I am do not know everything; it is a big subject).

When you say 'mental health problems' it is worth noting that 1 in 4 people suffer menatl health problems at some point in their life so remember you are dealing with people.

That said, if you would like a copy of an article I wrote on this subject a couple years ago email me at gault.shropshiresafety@gmail.com There is a lot more to it than can be fully covered inany article of course but it may be a start.

"Another thing to think about is sexual harassment etc"

But who harassing who?

Listening to a gaggle of central heating "engineers" discussing the days work, I am thinking that protection of the customer should be there somewhere.
Are your engineers DBS cleared/checked?
I ask because in many cases people with mental/emotional problems are regarded as vulnerable adults.