Changing the front indicators

[Quin8]

As someone who's not nearly as competent, or confident, in going anywhere too close to major S mechanicals, I feel I still ought to be able to change the cracked front indicator lenses! I've bought two new complete units, which are, apparently, slightly different from the originals. Steve Heath says that by unscrewing the lenses from the front, there's no need to get to them from inside the bonnet, as they will simply come out in one, with the bulb in the housing. Anyone got any experience of this?

Oh, and while I've got your attention, does tightening up the driver's door mirror simply involve screwing the wing mirror assembly back in?

All advice gratefully received, thanks.