Complex sentence: In 2006 Alliance UniChem merged with Boots to form Alliance Boots, subsequentley in 2008, European branches re-branded to Alliance Healthcare leaving only the UK operating under UniChem.
Split into simpler sentences: In 2006 Alliance UniChem merged with Boots to form Alliance Boots. Subsequentley in 2008, European branches re-branded to Alliance Healthcare leaving only the UK operating under UniChem.