Not to sidetrack too much about South West Surrey, but for reasons I didn't really understand the LD candidate was not eligible in 2015 and they backed NHA candidate in 2017 so there's no recent GE history here.
I’ve mentioned that on previous Westminsterender threads: it was very odd.
When Jeremy Hunt first took the SW Surrey seat (2005?), the votes were much closer - in fact, he once told the local paper that he considered the seat marginal back then.
In the 2015 election, something odd happened to the LibDem candidate. Both the people who’d signed his papers withdrew their endorsement, saying he’d forged their signatures. He was suspended and convicted at trial, I think.
It’s odd because he had no need to do it: the LibDems are quite strong here and any number of them would happily sign election papers.
So that gave JH a practically clear run at a massive majority.
In the next election, the NHS candidate was at first endorsed by both Labour and the LibDems and they got behind the campaign. Then the national parties told them to stop that and campaign properly for their own parties. Lots of confusion, three local Labour members were expelled, anger and recrimination all round and, again, JH walked into his seat with a big majority because those who would have voted against him either didn’t bother or split the vote.
So the SW Surrey seat may look like a huge majority on paper, but could actually be much more shaky:
It’s a Remain area and, while JH was a Remainer, he’s changed his mind and even seemed to support No Deal. That’s infuriated Remainers, but he had his eye on becoming PM and no doubt thought he could placate the locals in time for the next GE;
There’s been a lot of house building - I won’t bore you with what’s been going on there, but it means a lot of people moved into the area who are not traditional Tory voters;
JH is not having a good campaign.
He’s been too invested in national politics and his own career so he has very few local achievements to list. He’s been reduced to boasting about the Olympic torch in 2012 and shuffling X-Ray machines from one hospital to another (thus reminding the electorate that hospitals, largely thanks to him, are so cash-strapped they can’t afford their own equipment!).
Contrast that with a popular and well-known LibDem candidate and you’ll understand why the Conservative party faithful are firing both barrels every time PF so much as likes a post on a certain Community board 
.
Gosh! That was a side-track and a half!
Oh, and Guildford are furious that Boris Johnson considers them expendable.
Really, you’d almost think someone somewhere wants to crash the Conservative Party in Surrey, wouldn’t you?