The ABA doesn't recognize any online law degrees, which explains why your looking at the non-traditional route. I don't know anything about the University of London External Programme, but I do know that California is the only state that will allow an online law school student to sit for the bar, and California doesn't offer reciprocity, so passing the bar in California doesn't help you if you want to practice in another state, although several states will allow you to practice in their state after you have practiced in California for 5 years. You can also practice in Federal Courts, but good luck finding a job where you can do this as a lawyer who is just starting out. There is also already a glut of lawyers trying to find work, so it is not likely that the ABA will start recognizing online schools anytime soon. There are already over 200 traditional schools with ABA accreditation, so imagine how many lawyers would exist if the ABA started recognizing the online programs where tens of thousands more students could enroll (~~shudder~~). Additionally, even in California employers may not look upon an online law degree with much love, and since there are only 5 online schools and 7 correspondence schools employers will know who you are, as your law degree might as well be stamped "earned online".
As I mentioned, I don't know anything about the University of London External Programme, however "foreign" lawyers can take the bar in California and New York (maybe a couple other states). This might be a better route than California, because the New York bar is easier than the California bar, and if you can get a foreign law degree then you could take the online Master of Laws (LLM) program offered by Washington University Law School that was designed specifically for foreign lawyers. This one-year-long online program is recognized by the ABA, and Washington University Law School is a top-tier school, although not one of the Top-14. Getting accepted into the program might be a pipe dream. However, if you could pull that off you might have a chance of finding employment. If you don't get accepted, there are other online LLM programs (NYU has one for taxes). Then again, some states might not let you practice without a J.D. even if you have been practicing in Cali or NY for the last 5 years, so where you plan on practicing is kind of important.
If you decide to go the California route, I've listed the twelve non-traditional schools below:
Distance learning [or Online] schools ---
Abraham Lincoln University School of Law (Los Angeles)
www.alu.edu
Concord Law School of Kaplan University (Los Angeles)
www.concordlawschool.edu
American Heritage University School of Law and Public Policy (San Bernadino)
www.amheritageuniv.net
St. Francis School of Law (Redwood City)
http://www.stfrancislaw.com
California School of Law (Santa Barbara)
http://www.californiaschooloflaw.com
Correspondence law schools ---
American International School of Law (Irvine)
www.aisol.org
Oak Brook College of Law and Government Policy (Fresno)
www.obcl.edu
California Southern University (Irvine)
www.calsouthern.edu
Taft Law School (Santa Ana)
www.taftu.edu
International Pacific School of Law (Los Angeles)
www.paclawschool.com
University of Honolulu School of Law (Modesto)
www.universityofhonoluluschooloflaw.net
Northwestern California University School of Law (Sacramento)
www.nwculaw.edu