As an aside, it’s been underreported that the Lib Dems held on to every one of their massive by-election wins in once-safe Conservative seats. Unprecedented. Going forward this is bad news for the Tories. They’re not going to be able to shift the LDs out of the GE seats taken from them.
My previous attempt at voting tactically was voting LibDem when living north of Woodstock, when it was irredeemably blue. Seeing Charlie Maynard turn Witney orange is very satisfying - the Chipping Norton set may never recover. 😄