Let us be clear on grasses:
gramineae. For allotment purposes there are just two types that we need to consider. Annual grasses and perennial grasses. For most purposes, just digging them in is well enough. Annual grasses will all did in. Of the rest, most, like rye grass can be turned in to the soil too. In fact, you can use Italian rye grass as a winter green fertiliser. It keeps annual broad leaf weeds under control at the same time. there are two absolute blighters in the perennial grasses. Moorland tussock grass: It forms a large clump with a degenerate tussock at the top. The grass is tough as old boots, but dig it up with a fork and burn it. Do not put it in the compost, it will thank you for the bed and breakfast holiday and come back when you use the compost. (Okay if you compost it at high temp for nine months it will die). the other is couch
Agropyron repens. If you like digging this will give you much practice. If you don't, why have you got an allotment? Use a fork and carefully remove ALL of the rhysomes, (they look like spaghetti). Glycophosphates like 'Roundup' work but some think them dodgy. Careful removal is the thing, in autumn is best as removal of all growth from soil causes nitrogen leeching in high temperatures. Not dealing with A. repens can cause up to 40% less growth in crops, Wow! Finally if you have couch in your blackcurrants goosegogs or rasberries you will need to hand root them out with care. And never ever rotovate them. you will just spread little cuttings all over the place. hope this is of help, I just researched it on the net, (no I did not know it all before and am not a smart alec thank goord!)