Online Purchase Query

I want to purchase our 3 seats for the Spurs and Gills games but my son is a new season ticket holder so not eligible to buy til next week whereas myself and my father are ex withdean so are eligible to purchase now.
If i wait til next week to order them all together do i stand to possibly lose my 2 seats by waiting?
It states on the info that season ticket holders have til the 20th to claim their Gills seats but it doesn't say this re Spurs.
It seems silly to have to order seperately and am happy to wait til next week to order together but it is not clear when season ticket holders seats are held til for them to have to claim by?

Yes, you do run the risk, but your seats would still be together regardless of whether you split the purchase - as STHs can only buy their own seats - they are being held until further notice (at least the 20th July) subject to 75% of overall capacity being available.