Major on the vegetables that are not good quality when bought. Avoid cheap, or relatively cheap veg. Grow the best stuff. Runner beans, French beans, maybe sweetcorn, lettuce. Next year, new potatoes.
They have been quiet during the Winter because they hibernate. Now Spring has come and they are looking for food.
Smells lovely too.
Sorry, it's what birds do. Look at it another way. They are doing you a favour and eating pests; specifically leatherjackets.
If the cabbage didn't make hearts it is usually because they were not planted firmly enough in firm soil.
I would suggest they use a variety that has no scent. Supermarket freesias, and roses, etc have no scent. Shame.
All the things you mention are in the soil for a long time. If I were you I would take Dove's advice and grow things which are quick to give results.
Don't bother with Glyphosate - they are very easy to pull up.
Received wisdom is that one third of the branches - the oldest - should be removed every year.