In fact, it got to the point where I realised I was only ever hitting the arrow keys by accident while in insert mode so my vimrc now contains: inoremap <L

In fact, it got to the point where I realised I was only ever hitting the arrow keys by accident while in insert mode so my vimrc now contains: inoremap <Left> <NOP> inoremap <Right> <NOP> inoremap <Up> <NOP> inoremap <Down> <NOP> (the rest is at https://trout.me.uk/X11/vimrc https://trout.me.uk/X11/vimrc)