2 years ago fitted a flashing led to front of moho as the alarm led is mounted on the dash and cannot be seen when blinds down etc. then last month wired in one on the rear. Got to thinking might look more authentic if they flashed intermittently as the alarm (they are independent of it. Flea...
No SV Tech send you a new self adhesive weight plate displaying the downplated (new) weight, a certificate they have completed confirming the new revenue weight a V70 form and full idiot proof instructions for completing everything before submitting it all to the DVLA SV tech do not require your V5
If as in my case when I tried to do it myself get anything wrong and DVLA will just send you a new V5 at the current weight without an explanation they are apparently not obliged to do so. That’s what I ended up doing and on phoning them they claimed paperwork had been lost(more likely destroyed)
I have dug out my info re downplating.
As said you will need to submit a weighbridge certificate with your application.
On your V5 section 7 enter the new revenue weight and date of change. At the bottom of section 7 enter new tax class ie PLG then obviously date and sign section 8
Tried to do this myself last year turned into a nightmare DVLA claimed paperwork lost, in the end I bit the bullet and went to SV Tech, a breeze and all went well. If your doing it either yourself or using SV you will need a weighbridge certificate so unload everything you can before weighing.