Can I Transfer Existing Retirement Savings In To My Plan?

Yes, you can, although this may depend on the value of the pension you are looking to transfer.  There are rules requiring you to have received advice from a qualified financial planner for pension plans of a certain type and size.

The value of pensions can fall as well as rise, you may get back less than you invested.

Transferring out of a final salary pension is unlikely to be in the best interest of most people.