play houses are tricky...they bring a lot of pleasure to small folk but there are a lot of bad ones out there. not only are they pricey but they're going to sit in your garden for a while so best choose wisely (and be prepared to paint them - I'd advice black with yellow windows like derek jarman's cottage)
modern playhouse outdoor play house wendy house wooden

1/ tp forest cabin playhouse, £270, amazon
bay tree cottage, £1000, great little trading company
3/ go play junior, £921, the play house company
walton's honeypot stockade tower playhouse, £259.95, amazon