kingsize ziplink mattress similar to John Lewis Vi Spring Wembury

We have slept on a wooden bedstead for 38 years, current JL Vi Spring mattress is 11 years old. We now want a zip and link combination so we need to replace the bedstead with a divan. I have looked at Vi Spring divan sets but find the fully sprung base feels too springy and the recommended soft mattress too soft. I am 5'6", 9st7lb, my husband is 5'9", 14st. I have also looked at John Lewis Natural Collection and preferred the feel of their True Edge divan bases and the firmer edge of their mattresses. They now categorise their mattress into 3 levels of comfort - Firm, Comfort and Luxury and each level has 3 levels of quality - this is separate of course to spring tension. I liked the Herdwick 8000 and Angora 14000, and I understand these will feel firmer in the zip and link combination. However, I have been put off by negative reviews online for the John Lewis range and wondered what your equivalent would be in your opinion. For such an expensive item, it seems a bit hit and miss as to whether you will end up with a comfortable bed, and of course more so if you buy online! Please, do you have any advice? Thank you very much!