If you have access to the employee purchase portal at the Samsung website - I use Huddlebuy, but most employers have similar schemes, the Note 9 is currently £699. Then claim £150 cashback makes the net price £549.
Samsung Delivery & Returns Information
Samsung offers free delivery on all UK mainland orders.
Returns Information - Free 28-day returns, you may return products for any reason within 28 days from when you receive them. Items must be returned with all packaging, accessories, and free-of-charge products.