SJ,
Exciting times ordering a new Thorn bike! Thorn will replace the stem with a different one if you find the position needs changing once you have ridden the bike, just ask them within the 100 days guarantee.
You can also shorten the reach by using Thorn comfort bars, they have a rearward sweep which puts the grips a bit nearer than the straight type. My shoulders/back find these bars more comfy than the straight ones - it may be due to increasing age and reduction in flexibility!
I have the Thorn carbon stem in a 100mm length on my Thorn bike, It is a solid looking stem and inspires confidence when I ride with a 14kg load in the front panniers.
You can see some
photos of my bike hereIf you are looking to save some money, I fitted a
Smica Pro stem from SJS to a son's bike which is used for laden touring and, with a fork change, for mountain biking. He is a big lad, his previous stem was creaking but the Smica has performed well to date. The shortest one currently available appears to be 100mm and might be too long for you.
Julian