Mattress size and choice

Hi guys. Need help please. I need a new mattress my husband and I are rolling into middle of our sinkhole mattress. Definitely past its sell by date - husband that is. I have now reached a lovely age where my own temperature gauge is up and down like a yo yo. I do not want a latex or memory foam mattress. I overheat when I sleep. I would prefer natural fibers. Medium firm . - so I have measured my bed frame and it looks like it's 208cm length and width is 153cm -5ft? Is this a king size ???? What do you recommend please.