I had the cops round my house a little while ago after a neigbour called (here in England) and they were quite alright (they didn't know it was a HE of course

).
Speaking with them, it turns out that you can do annything that a scholl or college can do, but NOTHING MORE! even holding 'bomb making equipment' is a serious offence, even with alternate reasons for owning the indervidual items.
So basically be real careful, especially with the current climate as being 'suspected of involvement with terrorism' is an offence which gives you no actual rights, hate to get caught up in it myself! Whether it's 1 gram or 1 kilo, making such substances can be seen as aquiring the ability to produce such chemicals in a batch of any size so it is still pretty bad (although i'm sure you stand to be in mre trouble the more you have).