It's weird yeah mine is the Large but with the groove on one side like the Grand Daddy has but like you say they don't show or say it so it seems different now.
Master culinary skills with our durable Large Chopping Block, perfect for serious cooks. Extra-thick design for all your kitchen tasks.
www.mybutchersblock.co.za
That metal plate on the Grand Daddy seems silly as it means you can't flip it around and use the back without the groove which I do most of the time day to day.
That being said the groove doesn't really do all that much as you would think and either it overflows anyway or it never gets there to start with.
This must be a pricing error because this in a Large would have been an ideal day to day.
Stable medium-sized chopping board with lip for countertop grip. Includes juice groove for mess-free cooking.
www.mybutchersblock.co.za
I've heard they do quite a bit of custom work so I'm pretty sure if you reached out and asked they could make you exactly what you wanted.
I could never use anything less than the Large ever again.