Complex sentence: This is possibly due to the lack of promotion by Thom's label RCA Records, although there was some TV advertising, however Sandi has been promoting the album herself with album signings in HMV and also exclusive performances.
Split into simpler sentences: This is possibly due to the lack of promotion by Thom's label RCA Records, although there was some TV advertising. However Sandi has been promoting the album herself with album signings in HMV and also exclusive performances.