sixth form IS offers - how do they work ?

[scattycow]

We are thrilled that our DD1 has received 6th form boarding offers from 2 schools that she applied for. However, they both want to know by the end of this week if we accept (and pay a huge first terms money) them or not.

Whilst we are pleased to have them , we are still waiting to hear from our first choice (she is on the reserve list at the moment) and also from Hockerill - who as a SBS seem to work on a different timescale. Hunting back through these posts suggests offers from Hockerill come out around Feb time.

Is there a way to play this game ? Can we delay offers ? Can we say No then ask for it back if we don't get Hockerill ? I know its sounds rather unreasonable, but when they operate on different deadlines, its very difficult deciding what to do .
any guidance out there ?