On Saturday I will be collecting a pair from Gillingham and one from Deal. Pairs are better. It is less important that they all match (the odds of finding enough of the right size all the same are low) but as long as I get pairs I can place one each side of the ship opposite each other to at least keep uniformity.
The singles can be added into areas where rooms are on one side only (like the kitchen).
But while ebay is a good source I suspect I will still need to go to Trinity Marine in Exeter to get the bulk. Sigh. Its a long way and I will need a big van to both carry the cash needed and the portholes back.