Hi billabong1, when I moved from Scotland straight from the US, we found letting agencies / landlords wanted six months of rent upfront, as well as an increased security deposit. Usually the only way to get out of the 6 months upfront is to have a UK guarantor or a job right away. This was before the new Scottish rental laws went into place. I believe they can still request up to 6 months of rent upfront, but the deposit they can request is capped.
We were able to get a flat pretty easily in Edinburgh by viewing a property we found on a letting agent's site, then offering to pay the 6 months upfront. We moved after 6 months and had enough credit and verifiable income by then that it was no problem getting a flat with regular monthly payments.