Hi Hugh,
We are reviewing our Forum threads and notice that it seems you haven't got a reply from us regarding this question. Truly sorry for the late response and pelase see the answer to your question:
Currently it is not possible to remove a SKU from an SLP Online account. However, it is possible to “hide” unwanted SKUs so that they are not displayed in the table of available SKUs from which licenses can be created.
You can hide a SKU in "Manage SKU" tab -> "Edit a SKU" page (select from left navigation bar) -> see a list of SKU's and you can hide any of them by hitting the "Hide" button on the right hand side. Then when generating new licenses on "Create License from a SKU" page, you will no longer see these hiden SKU's.
--Peng