So I’m trying to sneak shiny bits into the house to upgrade my aging groupset. The road bike was 2nd hand off the classifieds and the previous owner was kind enough to swap the brakes to euro style for me. What it means though is I don’t know which side is normal for the rear and front as I don’t know if he swapped the brake cables over or just swapped the shifters around.

My left hand is the front mech (like MTB) and the right is the rear. Is this “normal” ?

That’s normal (for UK), yeah.

You can’t really swap shifters around, the levers would then shift by pushing them outwards, any thumb shifters would be on the wrong side, cables would leave the hood the wrong way, etc. etc.

Is this “normal” ?

Yes

Okay. I got a bit confused by someone selling a left hand 10-speed 105 shifter.