Seating Arrangements

Hello! Just joined because I have a question about seating arrangements; sorry it’s a bit long-winded!
In April 2005 I booked four seats in coach for my family of four to travel (through VH; we are Frequent Virgins) on VS005/6 in April 2006. In May 2005 I used VS’s on-line seat reservations to make sure I had reserved specific seats because (from previous experience of legroom problems; my wife and I are 6’) we wanted to travel in a two plus two arrangement by the windows. In January 2006 I checked the seats and found VS had re-allocated us to the middle of the plane (row 37 on VS005/ row 36 on 006) in four abreast, separated by the aisle. When I questioned this I was given all sorts of reasons (change of plane, operational reasons, one of our reserved seats was a ‘held back until check-in). I was told to make sure we were there as soon as the check-in opened to try and get better seats but nobody could tell me which seats would be available. Or we could use OLCI and try again, but with no guarantees. At all times the flight has been shown as a 346. Although I see VS005 has been a 744 over the last two weeks.
I joined ExpertFlyer to see which seats may be ‘held back for check-in’. Whilst the VS website shows all seats booked, rows 31-34 and 43-53 are missing on the ExpertFlyer site.
Can anyone tell me: if we change from a 346 to 744 what happens to the seat bookings, why the rows are missing from ExpertFlyer, which seats would be bookable via OLCI, will OLCI reduce our ability to get better seats at check-in, which seats are held back until departure, should we just try turning up (with our two young children) and take our chances.
Thanks.
In April 2005 I booked four seats in coach for my family of four to travel (through VH; we are Frequent Virgins) on VS005/6 in April 2006. In May 2005 I used VS’s on-line seat reservations to make sure I had reserved specific seats because (from previous experience of legroom problems; my wife and I are 6’) we wanted to travel in a two plus two arrangement by the windows. In January 2006 I checked the seats and found VS had re-allocated us to the middle of the plane (row 37 on VS005/ row 36 on 006) in four abreast, separated by the aisle. When I questioned this I was given all sorts of reasons (change of plane, operational reasons, one of our reserved seats was a ‘held back until check-in). I was told to make sure we were there as soon as the check-in opened to try and get better seats but nobody could tell me which seats would be available. Or we could use OLCI and try again, but with no guarantees. At all times the flight has been shown as a 346. Although I see VS005 has been a 744 over the last two weeks.
I joined ExpertFlyer to see which seats may be ‘held back for check-in’. Whilst the VS website shows all seats booked, rows 31-34 and 43-53 are missing on the ExpertFlyer site.
Can anyone tell me: if we change from a 346 to 744 what happens to the seat bookings, why the rows are missing from ExpertFlyer, which seats would be bookable via OLCI, will OLCI reduce our ability to get better seats at check-in, which seats are held back until departure, should we just try turning up (with our two young children) and take our chances.
Thanks.