Link:
http://www.caa.co.uk/application.asp...detail&id=1591
LASORS 2007 section G:
The aim of this course is to train pilots who have not yet received the theoretical knowledge instruction during an integrated course, to the level of theoretical
knowledge required for the ATPL(A). Applicants will be required to complete 650 hours of ATPL theoretical knowledge instruction at an Approved FTO within a period of 18 months. An applicant shall be the holder of a PPL(A) (excluding NPPL) issued in accordance with ICAO Annex 1.
LASORS 2007 Section J:
A candidate must complete all required written examination papers within 18 months of their first sitting, using a maximum of 6 sittings and no more than 4 attempts at an individual paper within the 6 sittings. The papers can be attempted in any order. A Pass in an examination paper will be awarded to a candidate achieving at least 75% of the marks allocated to that paper.
I hope this helps to clarify things. But no matter what it's clearly best to complete them in as short a time frame as you can! I do not suggest rushing through the study to the point of not actually learning anything properly- everyone will have their own pace set by personal circumstances, commitment, work etc...
LG