SDS is in Witney, Oxfordshire. Not a million miles from Gloucester. I'd be tempted to travel there and have a look. As I said, it's pretty good on consumables so even if you decide it's not for you on hardware, the trip wouldn't be wasted and you could offset travel cost against the p&p.
You can learn a lot from a face to face meeting with a stockist. Not sure if it caters for walk in off the street unannounced customers so might be sensible to arrange to go by phone contact first.