Time limit when changing number plates over

[Ads17]

Selling our car shortly and have applied to put the private plate on retention. Today the new V5C arrived in the post with the cars original number plate listed. The accompanying leaflet states the following:

Q. When must I change the number plates?
A. You must change the number plates using the enclosed V5C as soon as possible

Now I know they say asap but in reality how long can I leave the car on the private plate before changing it back to the original plate because 'as soon as possible' is open to interpretation. If possible I want to leave it 2-3 weeks (I have my reasons) before changing the plates over?

[Ads17]

Setting aside the "vanity plate" thing. If you don't like them fine but don't lambast people who do, each to their own and all that. The same argument could surely be put to many other car related items.

Anyhow from the DVLA I was expecting a notice to say you should change them within 2 weeks etc... not asap as it is open to interpretation. I have plates ready to go on but since there is a new car coming in a couple of weeks I thought I could save myself a bit of extra hassle and deal with all the insurance admin stuff at the one time, hence the original question to see if anyone knew if there was a actual time limit on it.

Looks like asap it is then!