Tax code help

SpeedSouth

Hi,
Just received my 2016/7 tax code through following my SA.

I'm wondering if they have it right. It seems weighted in my favour so don't want to under pay for the year.

I earn £45,000, so technically a HRT on a small amount, however I contribute via salary sacrifice 13% of this, which as I understand more than takes me back to BR payer. I was under the impression that contributing via salary sacrifice I didn't have to complete a SA or tell the IR as it just reduces my salary, and I wont pay any 40% tax. I've as well though had added to my tax code a Personal pension relief of £450 which in the notes alludes to the portion at 40%. (I can only assume this has come about following my SA as I've not asked for this)

Last year given I was not on salary sacrifice with my previous employer I made SIPP contributions to offset the 40% as I earned £50,000 last year.

As well I have marriage allowance transferred from my partner. I applied for this last year when I was only earning £35k. (Redundancy payout is the £15k uplift to total earnings last year). Is the MA the same deal whereby any contributions to pension funds are essentially reducing your gross income (the same as people do to maintain child benefit?)

To my mind I don't think I should have personal pension relief. The MA may or may not be due if my gross is reduced as per SS?

Hope that makes sense