Fitting an electric shower is cheaper than a new boiler boiler, but still not that cheap.
You're looking at £70+ for the shower, Then you need a plumber ? and you definitely need an electrician as you have to have part P, you need a new circuit back to mains board so not a quick/easy job. All in all probably looking at between £180 - £220.
DIY how to tutorial projects and guides - Did you know we have a DIY Projects section? Well, if no, then we certainly do! Within this area of our site have literally hundreds of how-to guides and tutorials that cover a huge range of home improvement tasks. Each page also comes with pictures and a video to make completing those jobs even easier!