Hi Clifford,
Be aware that if you select to do a course via distance learning means, the CAA class this as part-time.
I was in a similar situation to yourself (working P/T) and hoped to be able to get around 25-30hrs per week of study in at home. However, I was told by the head of groundschool at Atlantic Flight Training (who I can recommend) that I could only be credited with 15hrs per week, with the possibility of extending that to a maximum of 20hrs with evidence of the employment situation.
I'm pretty sure he said that the limit was imposed by the CAA - would definately be worth checking out, as the 600-odd hours you need can take a lot longer to do if you are only credited with 15-20 hours per week as opposed to 35 hours or so.
Regards,
Blueskyrich