Rainfall was pretty good over winter, and the front garden is pretty well mulched (the best its ever been) this could be part of the problem as well.

The garden is on a slight south decline and most of the affected plants are up against the front of the house, which is the lowest point in the garden and while I wouldn't say the roof's overhang casts a shadow the area doesnt get 110% full sun all of the time, all the mulch could be contributing to wet feet/root rot.

I'm going to try clearing the mulch around the base of the plants and adding some garden lime.

Is it normal as we head into the heart of spring for the lavender to become a little drier overall? At the tail end of winter/start of Spring the leaves were nice and soft, now it all looks a little drier (but not necessarily drooping)