There are very few plans of anything under St Day, namely the derivatives of Wheal Gorland including Muttrall. The sorts of things that you will get in the record office tend to be later (sort of 1820 onwards) and the St Day stuff (shallow) is earlier than that. Towards the west end, the rock is much worse and the shallow tin workings more frequent.
If you get St Day up on a map, you'll see Scorrier St is North-South, which is perpendicular to most of the workings in the area, the street will be crossed by workings, but unlike Vicarage hill, they aren't all the way up. I don't think Scorrier St has a history of moving.
From what I know, there are shallow tin workings in bad ground which sometimes move on the west of town. Vicarage hill has opened up a few times and has quite an interesting undulating surface still, Telegraph hill is right along a lode and Muttrall Footway shaft famously opened up spectacularly many years ago.
The various mining survey companies will have "drilled stuff" for various people and will have added this to their own records. This is not the sort of information they go throwing around, as it's valuable. They will be able to say "yep, there are likely workings under your house" because they've actually done drilling in the area. Of course, even when you take somewhere like Tuckingmill, for which there are plans covering every square meter, they often miss out the shallow ancient stuff which sometimes reveals itself spectacularly.
I think a mining search is about £50 ish. Failing that, your neighbours may have one.
If I was buying a house, I'd want a document which had been the result of some drilling ideally. The stuff off the plans is quite a gamble and if you read the small print, they often get themselves off the hook in the detail.
I lived in Glendale Cresent in Redruth for a while and the back garden opened up. Some hillbillies turned up, dug a big earthy hole and whacked a load of concrete in it. The whole end of the house was on the move with sticking doors &c. Two of my chums do surveys/searches for a living and the paperwork revealed itself for a sneaky off-record peak and we got out of there pronto! Mortgage companies quite often insist on proper paperwork with all the credentials but hillbilly estate agents working for unscrupulous landlords sometimes really don't give a toss. The whole area up there is on the move and the place was rented again....it's only a matter of time.