Re: 1570 used value
US vs UK is apples to oranges comparison. The US is a bigger market, prices are predominantly lower and the conversion rates aren't taken into account. For example, the Marshall Mini Refrigerator is priced at 399- US and GBP, odd that it is almost 480 Euro now considering when it first came out it was also 399-.
I am looking at one on a Belgium site right now (RG1570) and there is a one listed for 539- Euro. There is also a RG2750 listed for 500- Euro. On a Dutch site, there is a couple of RG2550Z listed for 750- & 950-. So honestly, I can't give my opinion on the price of the guitar that you are looking at due to the big difference in pricing that I just saw.
The best thing would be to post a bunch of pictures of it before buying it and having the more knowledgeable members verify it for you. The last thing anybody would want is you getting ripped off.