Nice review, very helpful. I've sadly been through a good many pages, nowhere near the lot though.
I think i've almost come to a conclusion on my choice/range. I was leaning to one of the Johnryan mattresses but i had a good scour on their site, and had a big of think about my current setup. The thing is, right now i'm sleeping on a forever old don't recall what or where purchased thing. I can literally see where the springs are as the fabric is sagging so much, but yet it's comfy enough. I'm light and do manual work and sport, plus i stretch daily. This is why i think it works okay. However my biggest issue with sleeping is heat, when cold i'm not massively bothered, but heat just makes my sleep really difficult. With all these supposedly good mattresses containing foam and dense filling, i just don't know how it's possible for heat to escape unless the materials are really good with transferring heat? Something with mostly natural materials i can only guess is best here. I'm definitely going for a standard solid wood bed, with nothing underneath to allow some airflow, and have my new setup in the centre of the room. Buy cheap buy twice. But why spend more than you need to? Why is this so difficult.
Glad you got some info, was just trying to save some headache since spent a good few hours reading it all.
To be fair, buying a mattress is not easy at all even with all this great info on this board even I am struggling.
Regarding your question though I do believe these modern mattresses or ones from last 5 or so years, the fabrics really do allow good heat transfer, I believe sleepeeze and others even do ones with Gel on top to take any heat away more. You can also improve mattresses from getting overly warm, swap to a summer duvet that is say 4.5 tog or less, I do this each year and also use a soft cotton mattress protector always, this seems to help me during those hot summers (my room gets 33c+).
Silk covers and silk pillow case covers may help get rid of heat, just not tried it though.
I still use my sealy millionaire memory mattress and its been fine, think it was over £300 many years ago from mattress man.
Having said all the above, I have since that last post, bought 3 different mattresses for another family member. One amazon mattress in a box, this one failed after 3 months since springs went funny and got uncomfortable, lucky got a refund from that since it was £100. 2nd was a sleepeeze mattress with 2000 pocket sprungs and top rated, this failed in 3 days, springs came misplaced also.
Then a sealy mattress, figured tried and tested right ? And went to test it and they appear to have left some plastic layer underneath the top cover.... so it sounds like you are sleeping on a giant walkers crisp packet, so that went back for a refund.
I think during covid, quality control has gone out the window not sure you can even spend £300-400 on a good mattress anymore since the amazon £100 mattress in the box did better then 2 x £350 mattresses.
I think it maybe better to go into a store, test it and then buy it, at least this is what I am advising my family member to now do, hopefully you have better luck.