A TV report dealing with the 40th anniversary of the marriage of King Juan Carlos I on 14th May 1962 included footage of his father, the (then) claimant Don Juan, Count of Barcelona, third male child of King Alphonse XIII, presumably in one of his rooms at Villa Giralda, his residence while in exile at Estoril (Cascais, Portugal). Two silk desk flags could be seen on a chimney shelf:
One was a square red-yellow-red flag, stripes 1+2+1 (i.e. a square national flag) bearing the pre-1931 greater arms of Spain (in oval shape, with crown and Golden Fleece collar) occupying the full width of the yellow stripe.
The other one was a square flag with a greyish (possibly silver or faded blue) field bearing a red Burgundy cross and on it a central emblem, possibly again the greater arms.
Source: TV report Especial Informativo: Aniversario Real, Antena 3 TV, 14th May 2002, 23:50 CET. The referred footage appeared around minute 29.