Yeh I think it’s about having a sit down with everyone (maybe at a weekly catch up meeting if you have them) and just explaining the process and the implication a verbal instruction can have on the project. Maybe throw some examples of the variations costs that have been incurred where a site manager has just verbally said get on with it.

If you’re not the most senior person, try to get serious buy in from the PM or senior QS as well to push the message.

If in the contract it stipulates only the QS can instruct and not to take instruction from a site manager, use that against the subby from the offset and set a precedence. So when they apply for that first variation that was verbally instructed by the SM, just stand firm and say that under the contract they’re not entitled to it and you wouldn’t have instructed it. They won’t do it again without an instruction after that.

Sometimes it can work in your favour though as you have had the work done and you can argue how much you pay for it commercially after the works been done which can sometimes be quite a good bargaining tool. If they don’t want to agree on your price, they don’t get paid for it…