Hi mumsgirl,
The pension lump sum was transferred straight into my bank account from the pension company. I then wrote to the DWP with proof of the amount. As I was below the 6k threashold there were no stoppages to my ESA. If your account goes over 6k then it is called tarriff income and they adjust your ESA, £1 taken off for every £250 over 6k.
My advice would be to contact Pensionwise, you can book a free appointment online, hopefully you can get an explanation about what you can do with your particulat pension.
Good luck,
Gaddy