Thanks for all the suggestions, i'm looking at the following, for those interested the prices are for a family of 4.
Monkey Haven - £44
Robin Hill - £88
Osborne House - £49.40
Godshill Model Village - £22.50
then onto a Fossil Hunt at Godshill £13.50
Wildheart animal sanctuary £51
then in to Sandown for the beach and gardens
Goodleaf tree climb at Appley park £33 each
Other activities (orienteering trail) in Appley park then onto beach
Arreton Down Nature reserve - free
then onto Garlic Farm for food - Tables can be booked in advance
Isle of Wight steam railway - £37
Amazon World - £50 or Tesco vouchers (i've been in touch, if using Tesco vouchers they need to be used on site, cannot be used to book tickets in advance)
I'm hoping where I can, to book in advance. I'm going to keep an eye on the places and if it looks like they are starting to be booked i'll book.
So far it looks like only the restaurants are getting booked up in advance.
In between these possible trips i'll be looking at the other options such as Alum bay etc.
Thanks again for your help.