As far as I know there aren't any short cuts for people in your position. Pilots converting who have 1000's of hours in multi crew aircraft may find that they are exempt of the classroom element of the ATPL groundschool but that probably wouldn't apply in your case. Instead you are left with 2 options. First one is a residential course which will take you about 6 months of being at school 5 days a week sitting the 14 exams over anything from 2, 3 or 4 sittings depending on the school. Second option is to do it distance learning or correspondence as you refer to in your post. I would say the majority of us do it distance learning. Generally speaking you work at your own pace and then when you feel ready book yourself into a brush up course a few weeks prior to the exams. All 14 of the exams run every month so again it is down to personal choice as to when you do them. You get 6 sittings in total, 3 attempts at each one and 18 months to pass all 14 from the date of the first attempt at the exams.
Below is a link to LASORS which is a hefty UK CAA publication. Section J has information on the ATPL exams. In the other sections you will find the requirements for converting your ICAO CPL and IR to JAA as well.
The CAA website has a list of the approved ground school providers. A search here on pprune will give you weeks of reading as this topic is generally debated on an almost daily basis. Bristol tends to get most peoples votes and they have an online database that you can access for a fee that has questions that are remarkably like those found in the actual exams. No wonder then why they get so many punters through the door.
LASORS