I need a drain cover, any suggestions?

[4th estate]

In my back garden, just outside the back door, is a drain which takes the kitchen and bathroom water. It feeds into the main drain, for which I have the manhole in the back, but that is ok.

My question is this, the minor drain has no cover. It is awkward to get at because of kitchen pipes for washing machine and dishwasher outlets. We put a temporary wire mesh over it to keep any rodents out (yeeeeuk), but would anyone know who would make and fit a cover?

Thanks.