Tax relief on pension contributions - 2 jobs but making APCs via one scheme

I have two jobs: 1. Part-time, low salary, contribute to a local authority pension scheme (LGPS). 2. Part-time, larger salary, pension situation that is non-LGPS. This gives total gross annual salary of c.£15k, split between the two jobs. I want to buy more pension years via job 1. LGPS scheme. I’m trying to work out the maximum additional amount I could pay per year and still receive full tax relief. Via job 1. (LGPS) tax relief would relate to the maximum of my salary and could be sorted via payroll. But - I understand the HMRC rule allows for tax relief on total annual income (up to 60k). So: If I made a lump sum of my total annual salary (both jobs; c. £15k), direct to my LGPS pension scheme rather than via payroll, could I apply to HMRC for the full amount of 20% tax relief on that? Many thanks in advance for your thoughts.

Hi Tortilla,
You can get tax relief on private pension contributions worth up to 100% of your annual earnings.
While there is no limit on the amount of pension contributions you can pay, you will not get tax relief on all your contributions if you pay more than your taxable pay into your pension in a tax year.
Also, there is a limit on the amount of extra pension you can buy in the LGPS by paying additional pension contributions.
The most you can currently buy is £7,579 of extra yearly pension.
The annual allowance of £60,000 is the amount your pension savings can increase by in a year without you having to pay extra tax.
If your savings increase by more than the annual allowance, you will have to pay tax on the excess. 
You can find more information via the LGPS website here:
 Tax
Thank you.