Actully VIN numbers are 17 digits (and technicly "VIN" is only aplicable to the 17 digit numbers as its done to a globally recognised standard, the earlyer vehicles had chassis numbers in a style the manufacturer made up in house).
Early Land-Rover VIN numbers tend to be 14 digits long as seen on the VIN plate as they omitted the first 3 clarictors when stamping (the 14 digits are stamped with BL logos at each end). The missing letters are the manufacturs ID which in Land-Rover's case is "SAL", which you'll need to add when quoting it as a VIN number.
Most VIN equipped series I've seen have the VIN plate under the bonnet eather on the bulkhead or the master cylinder bracket where as earlyer ones tend to be on the bulkhead inside the cab (eather infront of the gearleaver or beside the steering wheel on some metal dash models - easy to hide if someone adds extra instrements!). Militry ones are sometimes on the seatbox. Fact is there is no set location as vereous have been used over the years and the plates are easy to move or hide behind trim or sometimes not transfered on a bulkhead swap!
As far as the chassis stamping goes I think the front right outside face of the dumb iron on the thick bit where its welded to the chassis is pritty common for 88/109 but if its had new dumbirons, plating or is rusty it might be missing/no longer visable now. 86/107in have them on the rear left spring hanger.
I think when MOTing a vehicle the VIN number (but not the older chassis numbers) should be inspected so if you have a VIN era vehicle and can't find the plate you might want to do something about it.