There appears to be a bit of confusion on here as to what survey is what. A homebuyers survey is an optional basic survey to make sure your prospective house is in good order – electrics work, taps run, guttering, roof slates ok etc. basically everything non-structural that could potentially be quite expensive to remedy. they are generally recommended for houses over a decade old or so.
A building survey is what used to be known as a structural survey although they don’t actually do any structural testing but they do go into more depth as to looking for obvious cracks, potential for flooding, drainage plus all the homebuyers survey stuff. these are generally recommended for older properties – our house is over 100 years old so we bought into the idea of having one of these.
They don’t do any destructive testing of any sort and will generally recommend you to get ADDITIONAL surveys done like timber survey, drain inspections, damp survey.
The survey done by your mortgage lender is nothing more than a verification that your house is, well, a house, and isn’t just a pile of rubble and has nothing to do with the above additional surveys.
all are mostly a waste of time although the mortgage one isn’t optional!!