Complex sentence: In the UK, he holds no qualifications in, nor is listed in the national specialist register for general surgery or obstetrics & gynaecology because he was based in the UK in a research capacity.
Split into simpler sentences: In the UK, he holds no qualifications in, nor is listed in the national specialist register for general surgery or obstetrics & gynaecology. UK doctors' registration because he was based in the UK in a research capacity.