Hi Nii,
Sorry to hear your old Sherwood is not holding up after 13 years. It can be a bit of a conundrum looking for a replacement as not only your bed been ‘broken in’ to your body profile, but you have adapted to the mattress over time as well as your profile likely changing over the years - in other words even if you could replace the Sherwood with a new one if the exact specs, it might no longer be as comfortable or supportive as it once was. Thanks to @TheCleanBedroom for your recommendation, and @BillyIdol for your feedback!
Remember, any mattress you choose will be based on your Stats (height, BMI, sleeping position(s) and any underlying health conditions), and your PPP (Posture & alignment, Pressure relief, and Personal preferences). You can see by comparing the Mattress Specifications You Need To Know to the Mattress Durability Guidelines, how different materials may hold up over time.
Since it seems you have not decided on whether to go eith a foam or latex hybrid…keep in mind that we suggest any foam in a potential mattress has no more than an inch or so of lower grade foams (for memory foam no lower than 4 lbs/cuft for normal range weights, and 5lbs/cuft for higher range weights) and if polyfoam is used, with at least 1.8 lbs/cuft density, just to ensure you have support.
Thanks for providing all the specifications for the Urban Matttress offerings you are considering! ‘cold foam’ is just the name of the process for manufacturing certain polyfoams; a ‘high resiliency foam’ is a polyfoam which distributes pressure across the entire surface of the mattress, so it ‘bounces back’ to keep its original properties for longer. The density of the foams in these two beds are not up to recommendations, especially for larger sleepers, and unfortunately I would not expect either model to hold up over a long period of time as your Sherwood did. The Purity has an organic cotton and wool cover with .5" of plush latex over 2" of firm latex, so sleepers who want a softer surface (but don’t want to ‘sink’ and bottom out on the firmer layers below) may enjoy this mattress. A lot of your questions really come down to preference rather than any set ‘rules’.
Mattress Makers has been a Trusted Member of the site for many years, and they consistently manufacture quality sleep solutions for consumers of all types. The Delmar is a good quality made latex hybrid, with 3" of organic cotton on top of 3" of organic Dunlop Latex rubber with an 8" pocket coil unit with quad support, while the Kensington allows the option to flip the hybrid mattress to ‘even out’ wear on the foams on either side…which may be something you want to consider with your doggo hogging the bed at night!
I would consider your options as you presented them as only you can judge the best mattress for yourself. Don’t let anyone at any retailer or manufacturer ‘tell you’ which mattress you need - unless they are considering your Stats, PPP, mattress history any after a conversation with you. Present you with some choices based on this. It sounds like you are ‘doing your research’ so far, and a bit more consideration should get you onto the perfect replacement mattress!
~ Basilio