I don't want to give advice that is inappropriate or causes problems, so do not take my experience as advice... just take it as a testimonial.
In November of 2016, my husband and I moved out of the house we'd been renting near Salisbury and into the house we purchased in southwest Wales. From then until he stopped working at his old job in Salisbury and started working his new job in southwest Wales in March 2018 (about 16 months), he commuted to Salisbury every Monday morning, and came home every Friday evening. During the week, he stayed in a campervan on a campsite just outside Salisbury. Then he came home for the weekend to refresh his clothes, relax, regroup, spend time with me. He received his post at our house in Wales. We kept in touch throughout the days when he was away via email and text messages.
I applied for ILR in person in May 2018, about 6 weeks after his last weekly commute. We submitted the regular six pieces of correspondence to show cohabitation, but we also brought a record of how we kept in touch when we weren't together, in case they wanted it. They didn't question his employment address, or anything to do with the mid-week separation, so we didn't submit the evidence of regular contact.