Those cracks are not the normal sort of crazing one sees in perspex windows. They appear to radiate from the port light fixing screws , proabaly because there was insufficient clearance to allow for expansion and contraction. When you fit the port lights in the new windows be sure there is adequate clearance.
( Countersunk screw heads are another potential cause of cracking hopefully though you are not countersinking screw heads into them)
Initially the port lights began to weep water, then the cracks got worse, then the perspex (or acrylic began to leak too, so the only effective way really is to replace them.
This is one of the advantages of 2020 - I have lots of time too attend to these items rather than spend my time (& money) actually sailing!
I sent drawings, discussed fixings.
I dropped off the opening lights in order that the openings for them could be perfect.
He made the items, I picked them up the day before lockdown and fitted them at a later date.
(actually I have one of the pair yet to fit, the one I did fit was perfect.
I did the travel as it was easier then getting carriers involved from where I was.
Hi. Did you fit the windows to your Hanse 350? How did you get on? Was it easy? What procedure and products did you use? Having the same issues. Thanks.