Question: Mention the series code of countries using pound sterling as their currency unit. Which country belongs to high income group among them.
SQL: SELECT DISTINCT T1.CountryCode, T1.CurrencyUnit, T1.IncomeGroup FROM Country AS T1 INNER JOIN CountryNotes AS T2 ON T1.CountryCode = T2.Countrycode WHERE T1.CurrencyUnit = 'Pound sterling' AND T1.IncomeGroup LIKE '%high income%'