Help fixed penalty for phone and seatbelt at lights, Just left supermarket car park barriers Options

[Stan134]

Advice please

Last month I left supermarket carpark and took off my seatbelt to activate barriers by putting the parking card into the slot in the barriers.
I drove into a line of static traffic opposite the barriers just as the traffic light turned red. I did not have time to put my seatbelt on as I had to drive through barriers into the static traffic.
My car was at a standstill
I reached for mobile phone to check time
At which point Metropolitan Police who were standing on the pavement knocked on my window.
I explained all to the Police (not using phone/texting - seatbelt removed for barrier) however they pointed out that I was holding my phone and I didnt have my seatbelt on so I had no case to argue.
I have received two Conditional Offer of Fixed Penalty
£100 for seatbelt and fixed penalty £200 plus 6 points for phone.
I have low work income and in receipt of benefits
I have no points on my licence
Should I contest this? I dont want to risk incurring any additional costs as its already loads of money. Would I have to go to court in person as I'm not sure I'm able to do that

Thanks

This post has been edited by Stan134: Wed, 31 Jan 2018 - 12:35