Hi HFisher,
Box 1, is the gross pension payment that you made, which included the tax claimed back by the pension provider (do not include anything paid by your employer).
Box 1.1, is the amount of one off payment made.
This will allow you to claim higher rate tax relief on your pension payments.
Please have a look at the pension scheme rates here:
Pension schemes rates,
You can check you annual allowance threshold here.
Please have a look at the guidance for calculating your annual allowance and carrying unused allowance forward.
Any payments that exceed your pension allowance should be declared in a Self Assessment tax return in the additional information section (SA101).
Thank you.