Payment will be £100 as soon after sign up and your place has been confirmed. The remaining owed will be paid by the 1st Oct.
Efteling have come back - it's a no for hotel there as they insist on two nights, including 3 days entry. That's not valid for us. So I've emailed a few more bargain hotels today. Phantasia will hopefully get back today. Phantasia looks like I will book 12 "family" rooms, which is one single and one double. This might bump up the cost a bit.
It's also worth noting that the £/€ rate has dropped but hopefully the £15 pp safety net I put in will absorb any nasty surprises.
As soon as the hotels and Phantasia get back to me, the sign up will go live. Don't expect a fancy sign up, it'll literally be "submit this form"!