You need a step down transformer to use US electronic equipment in the UK. Make sure the total capacity of the transformer is sufficient for the wattage of the appliance, plus 10% to be safe. There's many around, and you can actually buy them in the US as well, but a good one will be heavy.
I have a simple cheapie bought from Amazon for about £13 that handles up to 100 watts; we also have a big yellow monster - like this:
http://www.airlinktransformers.com/tool_site_transformers/110v_portable_tool_transformers/RX033/Cheap, heavy, ugly, and mainly used on building sites, but will handle about anything you throw at it. Your computer and monitor are likely dual voltage. Computers have had a switch on the power supply since practically forever.
The transformer you referenced may be ok - it's rated for 750 watts. Check the wattage of the vitamix; the wattage on the other (volts x amps) is low, but bear in mind that it mayoperate differently on 50 cycle (US is 60 cycles).
I personally have a lot of stuff that I use with a transformer; DH has a lifetime's accumulation of tools that he uses with a transformer.
