Interesting. Based on an (admittedly small) sample of people I know I suspected as much.
This would be my guess of how it works based on the questions asked on the form:-
1. Gender is probably the primary screen. Being a man, I'm in trouble straight away.
2. Then age, I suspect. Mid-thirties prob adds to my troubles here.
3. Then location. I can't imagine they're underweight people from Greater London.
4. Then either postcode or occupation as a proxy for socio-economic group. I suspect they're not short of middle-class professionals are they?
Conclusion: My odds of getting a place are somewhere around zero
Interestingly my OH is male and in his mid 30's and Bristol would most likely count as middle class professional territory. He has applied in the ballot twice and got in twice... I'm mid 30's female applied in the ballot 5 times and been rejected 5 times