Why does pottery become scarce during the Saxon/Anglian period...

[Marc Berger]

Only slight drawback is that there's plenty of Anglian pot around here ...and plenty of timber buildings

Only if you call a finger and thumbed coarse lump of clay semi fired in a bonefire a pot, I think that the Romans might quibble. As for the timber buildings more like a few per parish and the parish system basically the solution that the Saxons had to living in a "Parkland" which is all they had to imagine a forest by-just enough large standard trees to make a hall so long as they all could bare to live in it, if not it was a hole in the ground covered with thatch -the same stuff they were firing their pot with (although I am not sure how much living was ever done in SFB. Ridge and furrow may also have been a solution to sharing out the resources of living in a parkland/parish. By the time of the Normans sentimentality (and establishing a prior authority) for the time before saxons resulted in creating the nova foresta which is probably what the saxons imagined the land scape like before they built their hamlets. Which is hardly an example of an optimum climatic forest although I don't imagine that's what the Romans found either. The Romans did though probably find far higher wood density (the local had just about descovered wheel thrown pot presumably fired using locally high density climatic optimum forest) to indulge their every whim which is basically grey wares centred near Peterborough an area returned to in the post med when the self firing feton brick became popular in London which I have wondered whether the nene colour coated wares relied on same the low calorific firing properties of the clay.
What the Romans left the Saxons basically was not enough to fire regionally centred pottery types looking for continental markets which wasn't too bad for the Saxons because they had basically been trained to survive the frisian islands and that required a communal midden. Respect the poo hitting cadastral social engineering..