No you will find beach towels in your cabin, however, if you want to take them ashore then you do need to take your own, the ones supplied are for the pool and sun deck.
You can take the blue towels ashore with you. Don't leave them behind though, as you'll get charged for replacement.
We are also going on 11 October from Glasgow. R U Glasgow or Edinburgh. You normally get towel.
We have been on OV1 twice and did not take any towels, white ones are provided for inside the cabin and blue ones for pool and beach - enjoy it's grea.