I completed both tests last night.
The first, I found quite straight forward. Before the test, I had practised using some of the free situational judgement tests you can find on the web. I was pleasantly surprised when I came to do the actual test that the options were fewer and the situations more straightforward (in my opinion).
For the second test, I done one hour of (Scotrail provided) practice tests. The problem is that you are literally repeating the same practice test time after time. My score was improving, but only because I was beginning to recognise some of the patterns. When I went to do the actual test, the new sequences really stumped me. I knew I hadn't done well compared to my practice attempts.
Alas, the rejection email came through today.
Good luck to anyone still to complete the tests. In the 48 hours you have to do them, I'm doubtful as to how much preparation you can effectively put in. I think you would need to be practicing over a longer period in order to really make a difference to your score for the second test.