You could have Lucas Atelier build you one: https://luciusatelier.com/products/explorer-watch-case-v2-36mm  The case is very nice, the bracelet is pretty nice, the clasp is OK.

San Martin also builds great quality watches, and has several explorer homages.

If you are willing to go up a couple mm in size, checkout astorandbanks.com/products/fortitude-lite

I've had a mostly positive experience buying and selling watches on reddit.  I bought a couple things, then started selling cheaper watches (under $100) to build up some transaction history.

Given you are in England, it's probably going to be more challenging since the reddit audience is US centric.

You can do some of the break-in by just working it in your hands before installing it.

Softest I've gotten out of the box thus far was a Fluco Nizza Cognac Suede strap.

Unlike poor Alessandra, the SM300 does get a bit of love on YouTube, but I think it took folks a long while to warm up to it.  I also think you may need to be a bit of an Omega nut to be willing to spend that much $ on low-bling vintage style diver.

I really like the look of the SBGJ201, but I also think it's too thick for the rest of it's proportions.  My 39.5 Planet Ocean is only 0.4mm thicker, and it's a 600m diver.

I think it's worth owning a bronze watch, there is a nice warmth to the look.  I do not think it's worth paying a premium for one, you won't get your money back on the used market unless the watch is still on the hype train.

I'm not sure if that watch exists.  I want it to have a dive bezel, but be thin, comfortable, somewhere around 38mm, probably titanium...  a slightly smaller & thinner RZE Endeavour with nicer finishing would be in the ballpark.

I chose that exact Planet Ocean (I was able to get it used, mint condition, with box & papers for under $4,500)

The 39.5 isn't ridiculously thick, but it is a bit heavy for a daily driver in my opinion.  Fortunately, the bracelet is fantastic, otherwise the weight would be a big problem.

Omega did a really nice job of scaling down the PO, a lot of sub-40mm divers look incorrectly proportioned.