Towing caravan in Spain-Marker Boards

Where has the idea come from that long vehicle signs must be taken off  when leaving Spain? Lorry drivers don't stop and remove them. Lutz doesn't stop and remove them. Why do other caravanners feel they have to have temporary fixings so that they can take the signs off at the border? 

The user and all related content has been Deleted User

This is from the Club's pdf on marker boards - (which shows I wasted effort removing them in France - Apologies for mis-information)

Using marker boards in other countries

In order to display marker boards in the UK, your vehicle must fall into one of the following categories (confirmed by the Transport Technology and Standards Department):

 A motor vehicle with a gross weight exceeding 7500kg
A motor vehicle first used before 1 August 1982 and having an unladen weight exceeding 3000kg
A trailer with a gross weight exceeding 3500kg
A trailer manufactured before 1 August 1982 having an unladen weight exceeding1000kg

The marker boards are legal in Portugal and if the combined weight of your vehicles is over 3.5t they are also legal in France.

We have contacted both SOLVIT (which is an organisation set up to resolve problems caused by the misapplication of EU rules in Member States) and the European Commission who have both confirmed that Spain can apply this law to all vehicles circulating in Spain regardless of where they are registered.

Yes you will still need the marker boards. If you look at https://www.truckspares365.co.uk it will give you details of where they should be mounted, including distances apart and height from ground etc. Guardia Civil Trafico will get their tape measure out if you happen to get stopped. The easiest way is as AD says above to stick them on with double sided number plate tape.

The best mindset in my experience is don't give the Spanish authorities a reason to stop you. The fun bit is, if you speak Spanish, don't let on until the last minute, then berate them for what they just called you!!!