CV and application help please!

[theblairbitchproject]

So i've had 2 jobs within the same company- EXACT same duties. I'm writing my CV (last time I applied for a job I had no work experience!). Do I repeat myself for example:

X Company
Date 2013-2015
Y duty
Z duty

X Company
Date 2012-2013
Y duty
Z duty

Or can I do it as [FIELD] experience and then list my duties and then the company with the two different addresses like this

X Company
Y Address
Z Date

X Company
Y Address
Z Date

Also a couple of application questions:

*Will it hinder my application if I don't allow them to contact references before interview?
*Will it hinder my application if I don't state reasons for leaving my last position (it asks but isn't a required field?)

Also- do you attach a CV and covering letter even if it isn't required?

Unless there was a gap, I'd just put X company, 2012-2015, and unless the contract/job title/position was different.

I'd put a reason to leave and put something neutral, and that sounds good for the prospective employers, but without lying.
As for the references, I don't think it will hinder your application if you are still working and if there is nothing to suggest you'd have problems with them.

References, I think there are some sectors that like to have them first, like social services, but most are happy to wait. I was made redundant so put that I was happy for them to be contacted as I didn't have a working relationship to save.

I'd put a reason for leaving provided it wasn't due to misconduct etc.