Hi there. /u/itsallfolklore and I discussed what is essentially your question here.

The TL/DR of that is that the Anglo-Saxons were extremely aware of who built the Roman sites around England, and often how, and lamented the fact that they were often unable to replicate them. The use of Roman sites was a key element of English political symbolism, and by the late ninth and early tenth centuries, the English were capable of rebuilding substantial Roman structures and celebrated this accordingly.

Poems such as 'The Ruin' in The Exeter Book explore a lot of popular sentiments about the 'fading glory' of Rome during the period.