Gorse flowers sounds interesting, must try the next time I make some Rhubarb wine. 
What you do need to be aware of is Rhubarb wine can go in to secondary fermentation, which occurs in the following Spring normally. I once had about a dozen bottles of the stuff, sitting in a wine rack and about 5am one Spring morning the bottles started exploding! 
Works better than an alarm clock  
 Camden tablts are used to " Stop " the wine   once you take the fermentation to a calculated /tested level of alcohol  or in technical term it's used to prevent further fermentation . 
Don't forget to rack the wine off the dead yeast cell sediments into a sterilised clean demijohn before you stop it so it does not develop off flavours & fit a sterilized water filled air lock once again,   topping it up as needed with clean cooled boiled water .  Sometimes the stopping can take  several weeks,  the wine starts to clear ( even quicker if you add finings ) Then when it's finally clear re rack it of the sediments . Stopper it in bulk & store it in a cool dark place for a few months so it can mature in bulk with the tannins ,  mallic acid  & ester alcohols developing a deeper flavour for you . 
 Almost ice cold  gin clear rhubarb wine is something to behold & sip carefully as it can have a creeping rubber leg effect & put your teeth on edge if it is a full dry wine @ 14 % or so .