sorry for such a late reply , only just read the post .
Whatever you want to sow now would have to be spring sown grain NOT winter sown otherwise it won't seed up , you will just grow long grass/straw !!!
So you must make sure you get get spring sown grain , which you normally get from any agricultural supply merchant , where you buy your chicken feed etc etc... if they don't have any left , then you could just by straight animal feed ie ..if you wanted to grow barley just buy a bag of straight ,un rolled barley . You can also buy it like this from loads of local farms who supply anyone that wants it . They would be able to tell you the variety and if it is spring sown , as they grew it on farm . It has been ages since I bought any , but I should think £5-£8 would buy a bag. if you have no luck there , look online at wheat grass supplies ... companies sell wheat , barley etc , to grow for the grass that you cut and juice . They sell in very small amounts 500gms ,1lb approx , but they do sell in larger bags , but it is much dearer from these companies . If I remember correctly it was about £25 for a 20 kilo bag .....
I would try the feed store first though , and even if they haven't got sowing seed , they will have straight grain , plus they should know , if it isn't written on the bag ? , who grew it . So you can find out what variety it is.
Hope this is in time for you ...
cheers
Russ