Re Siblings: Rootschat does not favour publishing links to other websites, so I have to circumnavigate giving you an IP address for what I found. If you Google: ' Wadey Scaynes Hill' hopefully it will lead you to the lengthy Genes Reunited text about a Wadey family from that location. Below are three edited abstracts from Diana and Serena of Genes Reunited also claim to have a Mabel Wadey b1906 of Scaynes Hill in their ancestries which read as follows:
[1] Trying to find william george wadey born in scaynes hill sussex married ruth annie bartlett from kent. I know that he had brothers and sisters . he would have been born around 1900.
[2] he had a sister mable and my mother tells me he was born in scaynes hill . he died in 1972 and married in 1935.
[3] William G Wadey, Spouse Surname: Bartlett, Date of Registration: Apr-May-Jun 1935, Cuckfield.
Whilst one piece suggests a possible connection with a Brighton Chimney sweep of that name, another says they believe the matriarch was a Chandler. If so,she must have been an Amelia Chandler who married William Wadey in Horsham district in 1912. So you may have to consider that your Wadey family includes half brothers and sisters and Mabel 1906 having a different mother or father. (Sorry, but you did say you wanted suggestions/ideas on this)
I found 10 Wadey marriages in Cuckfield district (includes Scaynes Hill) 1934-1947, and although Mabel was about 40 then, perhaps there could have been some later born half siblings of hers amongst those. For example, a Frederick J Wadey (the F?) married an Amelia Wadey in 1941.
Perhaps you may also be lucky and find ESRO or a major mid Sussex library still has an electoral role for Scaynes Hill district from the 1930s or late 1940s
Roy G