mattress selection

Hi, i'm looking for some advice/guidance please. I'm on the verge of buying a new king size bed. I'm 5 ft 7 and approx 72/73 kg. I currently sleep on an ancient double bed with a memory foam topper. With a broken headboard. The whole thing needs to go! I'm on 'project bed' which is to create a sumptuous space for me to curl up in. I've been eyeing up a wooden bedframe with slatted base which i've seen online, but choosing a mattress is tricky. I get befuddled with all the choice. I came across your website a couple of weeks ago and am thinking of something from your range. My budget will be in the Origins range and i was thinking of the Origins 1500. However, i did start reading your info about latex, and began to wonder if i should consider delaying my purchase to save up for the Origins 1500 latex. I just don't know if it would be worth the difference in price for me. if it helps, i have been to Bensons for Beds to lie on a few mattressess to see what i like. I seem to have a preference for firmness ratings of 3/4 (their's go up to 5), so medium-firm, probably slightly more 4's than 3's. I liked the Sensaform 3000 which is 1050 pocket springs and has memory foam top, but i'm thinking of moving away from memory foam because they do get hot. I also like a 1000 pocket sprung one called Ophelia Ortho Comfort. Also, I tried their version of a latex topped mattress (Geltex) which i liked, but it was over £1000, i also tried some of their natural filled mattresses (wool, silk, cotton, cashmere) but the sales assistant couldn't tell me what percentage compositition they were. These were called Splendour, Santiago, and Grandeur (Reylon made beds i think?), and were very nice and comfy but out of my price range (i don't know why i tried them!). It's probably not relevant but i also want to mention that i do a lot of sport training, and so i do crave a mattress which will provide the best support and rest for my often tired muscles and joints, - as does everyone i suppose! If you could offer any guidance i'd be very grateful. Thank you Kirsty