There are two separate figures here.
There is the number signing on the Live Register, which is what came out this week. That includes all those signing on for JB, JA, or credits. Those on a 2 or 3 day week would be included here, which is why it is always published with the disclaimer that it is not a measure of unemployment.
Then there is the Standardised Unemployment Rate (SUR), which is currently estimated at 11%. This comes from the QNHS (Quarterly National Household Survey). This would capture those who were self employed etc who are not signing on, but excludes those working part time. It measures unemployment by asking if the person has worked in the last 2 weeks, and if not, have they sought work. So any active jobseeker will be counted there.
As it only happens every quarter, a new estimate is produced along with the live register figures each month.