Pension as a contractor through an agency

[DLCC]

I am contracting through an agency and have been for a year. Before this I was a permanent employee and have three pensions running from various companies I worked for. I am 44 in November and am getting a little concerned that I haven't been paying into a pension for the last 12 months.

Should I pay in to one of my existing ones, and if so, which one do I choose?

Many thanks