my Bsc was not bad-class B

I have deep concerns about doing my PHD in UK. I hold an Msc from my uni with a pass after going through family problems in the course of the program. I have finally decided to follow my long time ambition but not sure if i can get a self sponsored phd on part time in the life sciences considering my average score. Also, my currently job role as a BMS in the NHS and trying to pursue a phd on part time is also an area am afraid of, as only 1-2 day study day off is allowed at my place of work. Pls, how do i work my way through this hic ups