We have a lockup (brick w/roller shutter) which is £30/wk incl vat. That's just about manageable. I would like to have a bigger unit with an office but the rates, rent, sewerage, water, gas, electrics (not to mention paying office staff) mean we need to grow more first. I live on the 3rd floor and couldn't manage without the lockup though.
Unless there are a number of workers in your company it's unlikely to be worth it. Also beware of commercial property contracts... it's a minefield and you have far less 'rights' than with than non-commercial renting (full repairing leases (so you have to fix it up, even if it's in a state when you take it on), unknown rent increases within the term, cannot end the term early etc)