Recommendation for a new mattress for a 17 year old

Seeking new bed for 17 year old son. Double size. He is 6 foot 1" and weighs 11stone but will likely grow more and get heavier as is broad but slim at moment.

He sleeps on side, front and back and doesn't like a firm mattress.

Am looking at your Origins Pocket 1500 mattress with matching solid platform top base plus drawers.
Does this sound suitable?

Also, we have just bought a new Hypnos classic with wool and eOlus medium firm springs/" title="pocket spring">pocket spring mattress which I find comfortable but a little firm but it is on a platform top base. Will purchasing one of your sprung artisan bases help?

Finally, I'm assuming you don't offer a recycling old bed service? Thanks