Cut off the dead flower heads to prevent energy going into the seeds heads. The bulbs should remain strong for next year - at least that is what i have always been taught and done.

No they will not flower again this year. If you want them to flower next year you should leave the leaves to die down naturally and as they do so they develop the bulb for next year's flowering. If you cut back everything you are unlikely to get a good show next year. You can cut off the flowering stalk with the seedhead but not the leaves. It means it's a bit untidy for a few weeks but worth it in the end. You can give them a light liquid feed to if you want to.

you could always fold the leaves over and tie them loosely, this looks tidier and always works for us.

Cut off the seed heads but not the leaves. The bulb makes the flower bud at this time ( for next year) as the leaves die back naturally. As above if leaves are in the way, but loosely. Also a feed of Growmore is good.

Prestonlass, tying up the leaves isn't a good idea as this breaks the capillaries in them meaning that they aren't able to properly nourish the bulb. We feed our bulbs in pots with half strength tomato food once a week whilst the leaves are going back.

Some of my daffs had strong green leaves till mid June/July, I left them, taking off brown leaves as they withered. Those daffs grew larger and stronger flowers this year and split to provide me with several new daffs. It pays to keep the leaves for as long as - boring as they look and tempting it is to pull out.

Go Kildermorie! Gardens can't look perfect and sanitised the whole time... unless you are paying big bucks to have that happen!