It only happens when braking?
Is it worse on light braking?
If you brake hard, does the vibration go?
When you come up to a slow stop (light braking) do the brakes suddenly grab to stop?

If so, its probably "warped" discs. I had this after a trip to the alps got the brakes a bit hot and ended up causing problems. I had all of the symptoms above. I replaced the discs and my issues went away.

If you can, are you able to put the old discs back on? If you didn't have the problem before and it goes away, this will help rule out the issue. If you got the discs from a company like ECP, you can return them citing a defect and get a replacement set.

Tyres are all in good condition and the car only gets light on road use. I do have another set of perfect condition wheels with almost new Verde tyres I could fit to rule out a tyre issue.

Replacing front discs and pads made zero difference to my vibration issue.

None of the wheels are warm/hot after a good run and in neutral the car rolls freely.

No signs of uneven wear to discs front and rear, both rear calipers were replaced due to seized pistons.

I just took the car out and tested braking from 30 to 70 in 10mph increments.

Hardly noticeable from 40 but very noticeable from 50, 60 and quite extreme from 70. Maintaining even brake pressure from 70 the vibration remains down to 25 or so mph.

Driving me mad as car has always been so smooth. 2012 4.4 TDV8 Vogue Santorini black ivory leather

I think your only option now is to get a DTI and perform a runout test on all 4 corners. Something isnt straight or moving about in there.

Did you replace the rear too? L405 2014 SDV8 4.4 Autobiography
Corris Grey
Previously 2011 D4 SDV6 HSE Santorini

Only replaced the front discs and pads. 2012 4.4 TDV8 Vogue Santorini black ivory leather

If your vibration is being felt through the brake pedal and seats but not through the steering wheel then that implies it is the back that is causing the problem. Could be a warped disc, sticking caliper or sliders although the caliper would probably cause a build up of heat in one of the rear wheels. 2010 3.6TDV8 Stornoway Grey/ Black interior - gone
2005 4.4V8 (M62) Bonatti Grey/ Parchment interior - gone
1998 4.6HSE Blue/ Cream interior (can't remember exact colours) - gone
1977 White - gone (should have kept)

If your vibration is being felt through the brake pedal and seats but not through the steering wheel then that implies it is the back that is causing the problem. Could be a warped disc, sticking caliper or sliders although the caliper would probably cause a build up of heat in one of the rear wheels. 2010 3.6TDV8 Stornoway Grey/ Black interior - gone
2005 4.4V8 (M62) Bonatti Grey/ Parchment interior - gone
1998 4.6HSE Blue/ Cream interior (can't remember exact colours) - gone
1977 White - gone (should have kept)

The vibration is most noticeable through brake pedal, seats and floor. Iam going to replace tge rear discs and pads and see what happens. 2012 4.4 TDV8 Vogue Santorini black ivory leather

I think I have found the problem. My rear discs look perfect on the outside but having removed the passenger side the back is corroded and unevenly worn. Had to pop out for bits so hoping to finish the job tonight and get back to smooth braking. 2012 4.4 TDV8 Vogue Santorini black ivory leather