A34,
The first one although has Police decals on, the helmet is a fire/rescue service/civil defence etc or similar IIRC, and not a standard M35,40,42 so not much value, but could be wrong if it does have original decals.... ? a clear close up pic would be good.
The second is a M42 Single decal "Wehrmacht heer" helmet as for value couldn't say for sure but not as valuable as the third helmet, again close up of the decal if you can.
The third helmet is Luftwaffe M40 double decal and looks a nice example, (eagle is the second pattern) This helmet is the most valued one out of the three, as for value I haven't dabbled in helmets for years so could be miles out can only suggest you look at dealers prices etc, you need to overvalue them as for insurance purpose you would want enough to replace the item.