I would go for the two tickets are from the same dealer with the letters and B numbers added as a reference. Maybe cabinet B with a position reference? The letters TTR and MN could be cost codes, because if the 300 and 95 were ticket prices, there is no guarantee that was the price paid. That might fall down given the T would therefore be a 2 if it represents the cost. 225 might be too big a discount, but R could be 5. N could then be 0 and M either 8 or 9. If it helps, I also bought a lot with RB on the reverse of the ticket and a price of £60 on the other side. That would tie in with R=5 if the price paid was 50 something. This ticket was a completely different style, so presumably from different dealer. .