I don't think it's directly equivalent, however I was told by more than one admissions officer that a 60 points at level 1 would get me a place at brick uni (mind you I am a mature student). There is a SCQF rating against OU courses which corresponds to Scottish qualifications, if that's any help? Level 1 courses have a level 7 SCQF rating.
I've seen some universities (I found it on the Sussex website) that if you have 120 credits from the OU there's a chance of going straight to the 2nd year of university. So it's worth a lot more than A-Levels, and I've managed to get two unconditional offers with A103, but I do have the odd A/AS-Level aswell.
thats becauseat every single full time university course you do 120 points a year, but from what i know in certain courses if you havent done an a2 in a certain subject you have to do an introductory year in it so they shuld be roughly equivalent if universities swap them around like that.
All I know is that if you what to study with Edinburgh uni you have to have Open University Credits of at least 120 credits with 60 at level 2 or higher. Hope this helps in some way