I only showed my flight in and out of Thailand, 5 months apart. A 4 night hotel booking confirmation for the first 4 nights in BKK and electricity bill as proof I was in the uk.
I tried posting a few questions here and I'm pretty sure all were declined, and that's fine. When I looked at the reason why I was declined the reason is clear and I've received an answer from admin to the question asked. I think this is a great group, administered extremely well, but probably most suited to grown ups.