I have just completed my last module with London Met, with an overall 94% within 16 months. I work 37hrs a week, and found that I needed to get in at least 2hrs a night during the week, and catch up over the weekend.
The hardest part of the DL route is getting into a realistic study routine. It took me a coupe of months to adapt to the constant study after work. It does take some commitment to come home from work knackered and have the concentration to sit down in front of a book.
I found London Met to be very good (although I did use Bristol's question bank for revision as LMU IT system is a bit 20th century). London Met conducts the course over 3 phases, with a week's brush up at the end of each phase. This format and location of the university suited my job commitment, and holidays.
Good Luck with your studies.