An interesting question to which I found all your answers, however to be sure, I would rather let Neil Hobbs answer it in his easily understandable way. 
My interpretation is that if you are waiting in a caravan for a job, your day starts when the mobile rings for your first job, you take the transit so you are on domestic rules, and would use the example on page 46 below to record your hours. Domestic hours are 10 hours driving in an 11 hour day, (you know the one that couriers stick rigidly to)
There is an exemption for
vehicles used in emergency and
rescue operations. However,
recovery movements are not
necessarily emergencies. Each
case must be judged on its
merits.
avrouk.com/page35.asp
onlinerecovery.co.uk/Feature … beware.pdf
roadtransport.com/staticpage … tm#Inscope
EU
Drivers Hours Regulation EC
561/2006
dft.gov.uk/pgr/freight/road/ … sgoods.pdf
pages 24 / 25 / 26 / 27 / 46 are the important ones in this case!
Record-keeping choices for digital tachographs
For domestic hours operations, there are a number of options in relation to the use of digital tachograph recording equipment. These are:
1 ignore the tachograph completely and keep records of domestic hours using a log book. This may be the preferred option for drivers, operations or vehicles that are entirely out-of-scope of EU rules.
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2 use a log book to record domestic hours, but put the tachograph to out-of-scope. This may be the preferred option for those drivers, operations or vehicles that are mostly, but not entirely, out-of-scope of the EU rules. The out-of-scope flag on the tachograph recording will help to qualify periods where vehicles have been driven without a driver’s card (which is specifically recorded and reported by the digital equipment), where analysis for EU rules compliance has to be carried out occasionally for drivers using the vehicle.
The out-of-scope flag can be activated by using the digital tachograph’s menu - there is no need for a driver or company card to be in the tachograph to do this. This out-of-scope flag remains on the tachograph until either a driver card is inserted (or withdrawn) or someone changes it back using the menu. There is no specific legal requirement to record out of scope in this way, but it will indicate to analysts, managers and enforcement officers interrogating the equipment the periods of time for which the vehicle is being used on an out-of-scope activity.
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3 voluntarily use the digital tacho to record domestic drivers’ hours rules. This may be the preferred option for regular mixed driving drivers, operations or vehicles, or for those managers who wish to standardise record-keeping across a mixed fleet. If the operation falls into box B in the previous flowchart (ie domestic records are legally required), choosing to record domestic rules on a tachograph, rather than a logbook means that ALL legal requirements relating to the fitment and use of digital tachographs must be observed, including the production of records at the roadside for the current fixed week and previous 15 calendar days (to be changed to the current day and previous 28 days from 1 January 2008). When the driver takes over the vehicle, the driver should insert his card and use the tachograph to record his activities in accordance with the manufacturers’ instructions. At the beginning of periods where the driver is out of scope of the EU rules, the driver should put the out-of-scope flag on the recordings.
Mixed driving days and digital tachographs
If a driver is driving an out-of-scope vehicle during a day and then comes into scope of the EU rules whilst using the same vehicle (eg a 3.5t vehicle required to tow a trailer part-way into a day), the procedure should be as followed.
If you have chosen option 1 above, when the driver comes in-scope of the rules, he simply needs to insert his driver’s card. Using the prompts and menus he must enter details of his previous duty for that day - remembering that any driving under the domestic rules is classed as other work under the EU rules.
If you have chosen option 2 above, again when the driver comes in-scope of the rules, he simply needs to insert his driver’s card. Using the prompts and menus he must enter details of his previous duty - remembering that any driving under the domestic rules is classed as other work under the EU rules. The out-of-scope tag will automatically be removed when the driver enters his card.
If you have chosen option 3 above, the driver will already have his card in the equipment. He then must use the menu on the tachograph to remove the out-of-scope tag at the moment he becomes in-scope of the rules