I spent some time yesterday digging into historic polls in relation to terrorist attacks and elections. I was able to look at polls in various countries including Spain, Australia, Denmark, Sweden, Germany, France, and even Turkey.
My conclusion is that terrorist attacks during an election do not amplify right-wing parties; they amplify the existing biases and opinions regarding terrorism.
Countries known for a more left approach to dealing with islamic extremism and other forms of terrorism actually saw the left parties have a boost in the polls following a terrorist attack. Terrorist attacks bring issues regarding terrorism to the fore, and thus boost parties seen as having the "right" stance to "solve" the problem; be that tolerance or security.
Given polls in the UK that show most brits want a strong hand when dealing with terrorism, it is likely that this will boost the Conservative vote. This is especially true as Corbyn has been attacked for being "weak" on terrorism.
As such, I've updated my projection for the UK:
You may wonder why the Tories have gained so much in the popular vote in Scotland. The answer is they have not. There are a large number of seats that are tipped by a very small number of votes, and with the comparatively tiny increase in popular vote I expect from the Tories here, they would gain a number of seats, including that of Angus Robertson, whose seat is just too vulnerable to withstand gains of this strength.