An 'aestel' recently displayed by @samfogglondon, said to have been found at Salisbury (top left). This one had passed me by. Others from Warminster, 'Yorkshire', Bidford-on-Avon. https://www.samfogg.com/exhibitions/18/
The catalogue also includes this which is described as a copper-alloy book mount of c. 800 (8x8cm):