Normally the OP's post would be deleted immediately as it contravenes Forum Rules.
The OP states they are a business and therefore should not need help from a public forum where most of the contributors are not qualified to give 100% accurate advice which also complies with the various regulations.
As a business they must have suitably qualified people to carry out the work, especially a Gas Safe LPG engineer and an 18th Edition qualified electrician.
They must also comply with all the relevant regulations, both gas and electric.
Because of those requirements this topic is locked for any further posts until the OP provides evidence of the skill level of his workers.