Can't recommend any, Greenoff, but you may well fall flat on the floor at the prices, unless it's self- storage. Also be VERY careful re insurance - it is very expensive and some companies will NOT cover you for fire damage, which can be water from sprinklers.
I often use self storage, try Leicestershire yellow pages or Thompsons. If more people got rid of their junk/treasured possessions when people were viewing the'd sell a lot quicker. Who wants to see some other person's accumulated lifestyle when you are trying to project your own onto a place? It ain't expensive and it's money well spent.
It is indeed expensive, and my 'short-term' arrangement has now got to over 18 months!! Don't kmow about Leics, but I am paying £135 a month (including obligatory insurance) for a self-store 80ftsq unit (which fits most of the contents of a 2-bed house) with 'Safestore'. They're a pretty big company, so maybe that's why they're so expensive, but I didn't want to take a risk with my life's possessions, as some of the smaller ones I looked into sounded a bit dodgy.
The one I use is very modern and secure and is about half that price. People use it for the contents of their antique shops, overseas postings, RTW travel breaks. I'd shop around.
Phone a few and ask what they charge. The reason I say this is because all the messages are saying it is expensive and that was a surprise to me. We have about half our stuff in store at present (having something done to the house) and it is costing £10 per week to store locally. That is not the only charge though, because it costs a lump sum to take away and another one to bring it back (ours was a bit pricey because it includes a piano so more blokes needed).
So for a 6 month deal the low weekly charge and higher lump sum would be best for you.