"The Saint Man" & future readers, In the old days the warning sensors were part of the pads hence two different type of pads for the same car (with sensors & without sensors), people used to opt for the without option as they were cheaper £££££

, once you fitted the ones without sensors and either unplugged the old sensors or cut them off the light used to be OK on some cars (no prob's until next time the pads are low you aren't warned

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Now the pads are all the same on most cars and they have replaceable sensors and as "DaFlake" pointed out if these have been activated and the warning light has come on they need replacing (sensors & pads), if you spot that the pads are low and change them before the light is activated you shouldn't need to replace the sensors.
If you go to an old-school mechanic (for want of a better word), he would have fitted the new pads without the sensor and either cut the sensor off or unplugged it and then connector and discarded it with the old pads, so your warning light wont go off no matter what you do until you get it checked & sorted out, you need to see if the sensor is actually there & either see if the garage still has the old pads (if it hasn't been cut & provided the light wasn't activated in the 1st place), or replace it with a new one, you may then have a chance of the light going out.
"john chapman" & future readers, the same comment as above as for the "The Saint Man" & future readers, plus there is only you that will know how you have gone about changing them, what you have done, what you have replaced, providing everything is OK (replaced) , I would have thought the light would reset it's self (I may be wrong

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I have more experience with the 1st Gen MINI, but I can't see MINI / BMW going back a step making the warning light needing diagnostics to turn off especially on brake pad warning lights / sensors etc... etc... (again I could be wrong

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Also as "DaFlake" says, once the lights have been activated they sometimes also need a little drive for them to go out (so the MINI can perform a check of it's own), In my experience this is normally after an ABS sensor change / fault

(I may be wrong

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They (BMW / MINI) may have just changed the system to a sequence to turn the light off eg. press a button in a certain sequence to reset them, but these normally take a few years to come to light (kept secret)

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The users in question must have had the light's turned off by now, please enlighten us, so that we all know how it has to be done or how you got it done (light turned off).