Are there any negative effects to flavour and or texture to freezing breads/cakes and such?
I notice many layered cake recipes have to bake a cake cover it in a layer then cool or freeze in the fridge, is there any negative affect to the cake?
Not that I know of. In fact, freezing is usually beneficial because it keeps the cakes firmer for assembling, layering, and frosting. It also helps crumb coats adhere better.
I have frozen cakes from time to time and I freeze bread regularly as I make large batches of bread and freeze the extra loaves to last through the week.
I have not read authoritative science on this topic and so my answer consists of my own observations and supposition.
I have never noticed a cake deteriorate in quality. Even wedding cakes frozen for a year are often indistinguishable from when they were frozen.
On the other hand, my homemade bread does change. After a loaf is frozen, even if it is used just the next day, it will be slightly more crumbly than the loaves from the same batch that were not frozen. It is only a problem if the bread was too crumbly to begin with. In that case it may be impossible to even slice afterwards. I still freeze the extra bread as the change in texture is usually not enough to offset the convenience.
I suspect that the effect on the bread is because of drying. Though I haven't tested for it specifically, it seems like the crumbly effect is more pronounced in lower-hydration breads. My homemade sandwich bread is much lower hydration than an artisan or french loaf, for example.