There isn’t a lot about but dollwaggon zig zags from grizedale tarn usually hold snow and will be reasonably hard packed, make a day of it and go over nethermost to helvellyn then back down to wythburn nice loop if you park at dunmail and go up raise beck.
Yep, the lot tramping around on Lower Man in crampons for starters while we were in fell shoes which were more than adequate for the conditions, crampons would have made it bloody hard work in my mind.
If its just to get used to them on your feet then anywhere snowy is going to do - just make sure no one sees you walking on the flat in them though - they'll wonder why you are using them on flat, new snow.
You might want to be a little wary of parking at Dunmail and using the Raise Beck path to access a suitable crampon practice area. In these freezing days with little snow cover, there is a couple of steps on the path with a lot of seepage that often need crampons and that would be before you reached your practice area!