if you are after a wild meadow effect then I would leave it alone. you may find you get other things germinating that are happier in a 'water' meadow. it is prolonged flooding when the plant is underwater for a week or more that really puts paid to them. if you are really worried then lift a few germinating seeds are grow them on.

That's a good idea. See what grows there naturally and just let it be. Otherwise, there are certain plants that thrive in a bog setting if that's what you have - Sweet Bay Magnolia, Water Iris, Hydrangea, Swamp Maple, Willow - anything with a watery sounding name is a clue.

The flooding goes down if it stops raining. I didn't think of lifting some seeds SBG and will keep that in mind if it becomes a pond for a longer period.
Bathgate, it's not a bog garden. At least I didn't think so. It's just a patch of grass that I cut back and planted, but it is on clay. We don't normally get such constant rain even in Devon.
Thankyou both.

I'm not saying to grow a bog garden. My point is that certain plants do well in a watery situation "keeps being flooded' as you stated at first.