If you're NOT from a third world country, you probably won't have any problem securing a UK Visa. Hopefully, having secured a Schengen Visa might help in getting a visa for UK. Additionally, having a solid travel history is also pretty useful. I read somewhere that should you get your UK visa, you need to be careful in arranging your flight details. From what I read, normally UK visa grants single entry. So, hopefully you won't be entering UK, proceed to Schengen area, and back to UK for a return fight. That is, be careful in arranging your flights, as you won't be allowed entry again after exiting the first time, unless of course you are granted multiple-entry visa.