Here are various documents that I considered worthy of a high quality scan (according to this recipe). I provide them here for the benefit of others.

Manuals

Acorn BBC Master Reference Manual Part One

Acorn BBC Master Reference Manual Part Two

Acorn BBC Master Welcome Guide

The Advanced User Guide

The New Advanced User Guide

Acorn Speech System User Guide

Acorn Speech Upgrade Instructions

Acorn Cambridge 32016 Co-Processor Technical Description and Service Manual

Booklets

NS Series 32000 - The Specifics of 32-Bit Architecture and Implementation

NS Series 32000 - Series 32000 Architectural Support for HLL Code Generation Strategies

NS Series 32000 - The Benefits of Demand Paged Virtual Memory

NS Series 32000 - In Search of the Best UNIX Machine