We used Migrate.org.uk's DIY Application Pack to extend my wife's spousal visa mid-term. During our original application, we used a lawyer because of some complex issues but this time around wanted to complete it ourselves to save the small legal fortune(!). The guidance within their documentation is extremely clear and explict, removing the element of doubt from the concern of "have I submitted the right document in the right way". It takes a good few hours to read, plan, prepare for, and gather the documents, and then another few hours to double/triple-check everything but their guidance makes it a case of painting by document numbers. I highly recommend this service to anyone whom is wanting to complete the visa application process themeselves and wishes to have some expert guidance to help.