Is company limited to salary payments for company pension relief?

The company itself is not limited by salary. You can qualify for tax relief on contributions up to your earnings level (eg trading income income and salary from company). Therefore any contributions above this would not qualify for tax relief. This also includes the company contributions. However in terms of the deduction for the company, when it makes a pension contribition it is only required that the contribution is 'wholly & exclusively' for the purposes of the trade. If though a contribution was made with no salary etc it could be questioned whether this would satisfy this rule. There is more on this in the Revenue manuals (eg http://www.hmrc.gov.uk/manuals/bimmanual/BIM46035.htm)