drive by valuation or full valuation

[philv]

HI

Need to get a valuation by the bank for further borrowing against my house.

60 for drive by valuation.
250 for normal valuation.

How do they do the drive by valuation?
I realise they only visually inspect the front of the property from the road.
But do they look at the previous sales price and house percentage increases in the area as well?
Or do they consult zoopla or?

I am thinking of doing the drive my, and then if any problems asking for the full valuation.

But i wanted to know how a drive by value is calculated?

Thanks or any help