Lets not forget guys, LED's is the way forward like it or not. Allot of cars and bikes are sold new with LED lighting, they are brighter much more noticable and last longer. Thats not to say it gives us an excuse to go and fit lighting that is not noticable. We all want to be safe and noticable.
I have just ordered an LED tail light with intergrated indies however I wont be connecting the indies as I have already got LED indies plus personally dont feel safe with it. I have just been to my local MOT station with my indies for the front of the bike in hand and asked what they thought. Response was, fine so long as they are bright,the right colour and flash rate is correct i.e. not flashing red or very fast/slow.
It really doesn't matter on the size, its about the light emittance they give off. You cant regulate a light by size, its about the power rating, light emittance, colour and flash rate. If a 40mm indie gives off a brighter light than a stock bus light what more can you say, you will get noticed and probably more so. One, because its brighter and 2 because they look good

I'm in no doubt we put them on because of the look factor (I did, cant stand the stock look on any bike) but in this case the bonus is they are also brighter and more efficent.
Like I said before there are allot of bikes out there with LED lighting old and also new bikes, so either we are saying they are all illegal or not there is no in between and I tend to fall on the side of they are fine. It seems to me its more of a choice thing, you either like stock indies or not. Either way is cool, its your bike no one elses. I do things to my bike for me not Mr Jones and his likes or dislikes we are all individuals with freedom of expression....