I ordered a replacement brake master cylinder which I fitted., this turned out to have a leak from the reservoir. I notified the seller who bent over backwards to help me.I mentioned that I'd probably seal the reservoir up as it's not a pressurized part of the system and it's a massive pfaff to change everything over.
Upon hearing this the seller offered me a full refund, however I ended up selecting some other MR-2 parts that were useful to me. The same day those parts were sent out, and the seller has refunded the difference in price to me. Everything was done on faith, and I didn't have to return the master cylinder to him.
As said - very happy chappy. 
Check out their eBay shop: www.mrmr2.com
