The Teaching and Learning Materials offer excellent support, note the support for Statistics. The Teaching Guide is very thorough indeed, as Edexcel say:
“This booklet looks at statistics content of AS and A level Mathematics qualifications and is intended to offer explanations of the terminology that is being used in specifications, guidance on how to approach teaching of the content and help on where and how to use technology to support the delivery of the course. This document is designed to give teachers a starting point and does not include all possible approaches to topics discussed.”
For further information on the Edexcel specification and sample materials see this page.
Signing up to the wonderful Mathematics Emporium is highly recommended, note that it is a free website intended for the use of teachers of mathematics in secondary schools, regardless of what board you use. Register for an account and ensure you supply a correct centre e-mail address in your name for verification, your centre name and centre number.Some of those old A Level papers could be rather useful I suspect, a useful source of questions.
See also Mathematics A Level 1986.