We always recomend to post a job on main website because some of a job needs to be seen before any advice is given.
Our service is free of charge with no obligation quote and our tradesmans are happy to help with every aspects of jobs.
I would strongly recomend to post a job on Rated People home page then 3 companies will get in touch then you would be able to choose the right person as you would receive an e mail with a link to tradesman account where you would see a pictures and you will read revious from previous customers.
I hope this will help
It could be that the plant is an alkaline soil it prefers neutral to acid. Waterlogging is also resented prefering well drained but moisture retentive. Daphnes do not transplant well so could be settling in.
if soil is alkaline try some sequestrated iron granules around the base. It may be hungry after the effort of flowering so could try a shrub fertiliser.
There are numerous leaf spot diseases but diagnosis is difficult.
Is your plant straight D odora and not the variety aureamarginata which does develop a variegation on the leaf.
Sorry cannot be more specific.