Different market
The 201's were bought at a time when they were the only rtr Irish Diesel loco available and the prospect of any further ones being produced was not known
Nobody is arguing about the quality of the 141/181's, they are bulletproof.
These locos are still available from some retailers but when the 201's were making big money they were out of production for up to 8 years
Best price I recorded was £510 stg for a River Boyne in Jan of O9, and River Boyne had the biggest production of the range with 500 made.
They were produced in O3 and were still in some shops in O6, its really hard to fathom why it went for such big money.
In Sept of O9 an NIR 208 made £87.25 stg, but if I remember correctly the seller had a UK only tag on his listing so it excluded probably his biggest market
Anyway best of luck to Michel, plenty of people still out there looking for some elusive numbers to fill their collections.