Well my suggestions are
1. you could use something light to make into a pond. Even very small gives birds some water, and you will be surprised by the amount of different things come to try it. So you might use an old dustbin lid as a shallow but bigger shape, and then if necessary you could pull it across to get access to the drain. You could also plant up on three sides some grasses or simple open flowered plants which would encourage the pollinators to visit. Then you will have the fourth side to drag the "pond" aside . Then on the other one you could have a largish pot, but fill the bottom with something like polystyrene or plastic pots etc, to keep it light. Then fill with decent compost and put something of your choice into it. So if it is not a windy area you might use ericaceous compost and water with butt water and plant an acer. These come in many lovely colours and you could also plant underneath the acer something like iris reticulata or iris danfordeia. (cant guarantee the spelling for these plants) Alternatively you might look into getting two things that will hold water and you could have a little difference in heights so you could have a connecting electric small pump so that you had water falling from one into the other. Very peaceful to listen to. Or perhaps do the water or the plant pot on one and then put a small piece of hessian or could use plastic grass - which personally I dont like - and then make that the place you put your chair and have a little weatherproof table there so you can cover the place by sitting on it, but your feet could be on the real grass. Another idea is that you have a couple of low weight containers and you could fill them with annuals or simple things like a tray of pansies or wallflowers , which should take very little effort and take your eye away from the drains. I am sure you will get lots of ideas to try out. Enjoy it and take photos so that you can look back and see what worked well and what you might like to do again.
