gifting money to someone on benefits

My daughter is in receipt of New Style Esa , topped up by Universal credit because she has suffered from severe mental illness since her early twenties. She is in the support group. I gift her regularly out of income £550 per month which we have not declared to the DWP as we understood when she first went on to benefits that it was not necessary to do so. Some years ago, when she was still working my husband and I set up a small private pension for her ( a Sipp) as she will have no pension income in old age. We have carried on paying in to this for the last two years. We did not declare this either as we understood that pensions were disregarded. lately I have started to worry about this and wonder whether we should have done so. Does anyone know what the limits are on regular gifting from family members and whether the money now building up in her private pension could be considered as capital by the DWP. She is nowhere near pension age, so could not draw an income from it. Am i worrying unnecessarily?