I'm sure others are probably better placed to comment regarding sizes, but my two cents:
A chest measurement of 43 - no wonder your 38R didn't fit you any more!

Most jackets actual chest measurements are around 2.5-5" more than the tagged size, depending on how slim-cut they are. You should choose which size to go for on the same basis and taking into account the shoulder size too. Remember that most people measuring suits measure from seam to seam for the shoulder which won't exactly match your anatomical dimensions. Black Label is quite slim fitting, so going purely by the sizes you listed, I doubt the 42R would fit comfortably with only a 2.5" chest clearance esp. in light of your shoulders. 44R seems a better bet I would say. The trouser waist would need some sorting, but that's no problem for a tailor.
Please note, I don't do refunds for sizing issues unless my measurements are wrong... but at the prices I'm asking on eBay, even if it isn't a perfect fit, you should be able to flip it fairly easily!
Unfortunately, I'm away from home this weekend until tomorrow evening, so can't get you a thigh measurement on the suit until then. Black Label trousers are also quite slim fitting, but not anorexic skinny!

Best of luck, should you decide to bid.
If anyone else has advice for you, or feels I'm mistaken, please do post.