What is eating my runner bean leaves? A question on pea germination

Hi All,  I have noticed something is eating my runner bean maiden leaves and reducing them to skeletons despite slug pellets spread around the plant.  Whatever is doing this is selective too!!  White Lady and Enorma are being attacked the other three varieties are being left alone (Firestorm, Scarlet Emperor, can't remember the other variety) These are young plants and not started to wind up the canines yet.

My other question concerns peas.  Planted 100+ seeds 2" deep three weeks ago and only 12 have germinated.  after a 'firkle' there is no sign of the pea seed.  What is going on here?  The seeds may be 2-3 years old and stored in-doors during the Winter.  Varieties: Early onward and Claverdon Wonder.

Mike.

Thanks elizabeth1,
 I had not thought of snails, slugs - we have plenty on the plot but the pellets used tend to work.  It is strange, everything is eaten just leaving the leaf skeleton, usually slugs eat the lot!

Peas: The row is protected by a net closh closed at each end, there is no mice evidence - do they leave any?

Mike.