Use of Spanish 
The only Spanish traditionally included in the services is a translation of the Haftara on the Fast of Av. However, in recent years a Spanish table hymn – Bendigamos – has been introduced to the London community from New York, being sung immediately before or after Birkat Hamazon. Although not an authentic London custom, it’s been adopted as a sort of club song. It originates from a Spanish-speaking S&P community in Bordeaux that was destroyed by the Nazis.
♫ Bendigamos (MP3) You can read more about it on the Bendigamos page of the London Sephardi Music site.

Aramaic pronunciation Kaddish 

Unique – I believe – to the S&P is their traditional  pronunciation of three Aramaic words that occur in Kaddish:

• Kal instead of Kol
• Be-ngalma (occurs twice) with the accent on the second-last syllable (mil’el) instead of the last syllable as it is pronounced in Hebrew
• Ba-ngagala with the accent on the second-last syllable (mil’el) instead of the last syllable

One explanation may be that the S&P actually have a tradition that this is the correct way to pronounce these Aramaic words; but another may be that they simply invented it as a way of distinguishing them from Hebrew words that have different meanings but otherwise sound identical.

Yitgadal veyitkadash shemeh rabah.
(Congregation: Amen)

Be-NGAL-mah divera khiruteh, veyamlikh malkhuteh,
Veyatzmakh purkaneh vikarev meshikheh.
(Congregation: Amen)

Behayekhon uvyomekhon uvhaye dekhol Bet Yisrael,
Ba-ngaGA-la uvizman kariv ve-imru Amen.
(Congregation: Amen. Yehe shemeh rabah mevarakh, le’alam ule-almey almaya yitbarakh.)

Yehe shemeh rabah mevarakh, le’alam ule-almey almaya yitbarakh.
Veyishtabkh veyitpa-ar veyitromam veyitnaseh
Veyit-hadar veyit-aleh veyit-hallal, shemeh dekudeshah berikh hu.
(Congregation: Amen)

Le-elha min KAL birkhata, shirata, tishbekhata venehemata,
Da-amiran be-NGAL–mah ve-imru Amen.
(Congregation: Amen)

Kal Nidrey and Kal Hamira
Both in the opening word of Kal Nidrey on the Eve of Kippur, and in the annulment of leaven (Kal Hamira) on the Eve of Passover, the word for “all” is written without a makaf connecting it to the following word, and therefore pronounced “Kal” rather than “Kol”. This seems to be an S&P usage that applies to all appearances of this word in Aramaic rather than Hebrew contexts.