Your tone of voice defines who you are and how you will treat your customers; this should reflect your brand and should also be incorporated into any text you display whether this is online or on paper. A professional proofreading service should certainly be an option if you want to avoid embarrassing your business in front of the whole nation. How can a customer trust a business when they can’t even spell properly! It may not even be a spelling error, it may be a typographical error but, nonetheless, it will make you look daft. A professional proof-reader will be able to preserve your dignity and ensure that your message is told to the word in the right tone of voice for your business.
If you were going to talk to your buyer persona in real life, what kind of attitude and language would you adopt? This needs to be apparent in your text so that readers get a real feel for your business. You do not necessarily just need to look at copywriting agencies in London for assistance; you will be able to find a perfectly good copywriter close to home.