eBay API 'Invalid auction currency' error

I'm trying to add eBay listing through their API using SDK (ebaysdk-python). I run tests on sandbox.ebay.co.uk with Trading API Sandbox.

I am selling my products on eBay.co.uk and I want specify price in GBP. Products are shipped from Poland. With these params I have problem with GBP currency.

item = {
            "Item": {
                ...
                "Country": "PL",
                "Currency": "GBP",
                "Site": "UK",
                ...
            }
        }

api.execute('AddItem', item)

I'm getting an error:

AddItem: Class: RequestError, Severity: Error, Code: 95, Invalid auction currency. The auction currency specified does not match the auction currency for the selected site.

eBay API doc says: http://developer.ebay.com/DevZone/XML/docs/Reference/ebay/types/SiteCodeType.html so the settings seem to be correct

Solution was so obvious. I did not put siteid: 3 in ebay.yaml, now I can use GBP as currency.

# eBay SDK Defaults

name: ebay_api_config

# Trading API Sandbox - https://www.x.com/developers/ebay/products/trading-api
api.sandbox.ebay.com:
    compatability: 719
    siteid: 3
    appid: xxx
    certid: xxx
    devid: xxx
    token: xxx