Complex sentence: He represented Australia to Under 21 level but declined the offer of a Sevens cap (that would tie him to Australia) but instead was called up to the Scotland squad but was not capped in a formal test.
Split into simpler sentences: He represented Australia to Under 21 level but declined the offer of a Sevens cap (that would tie him to Australia). Instead he was called up to the Scotland squad but was not capped in a formal test.