What an interesting question to ask - not the usual one to be asked here!
I never saw these at Lisbon or elsewhere, but would have liked to have seen them. I can tell you a little about Aquila Airways, from a book I have by Tony Merton-Jones titled "British Independent Airlines 1946-1976". Here is a summary based on the facts given in the article.
Aquila was formed in 1948 and helped in the Berlin Airlift using Sunderlands and after that operated its fleet on both regular and special charters, such as flying many members of the British Olympic team to Helsinki in 1952. All this was done from its base at Southampton.
One of Aquila's most favoured destinations was Madeira which was operated twice a week. They also served Las Palmas as an extension and later went to other places such as Capri (Italy) and Montreux in later years.
They wanted to buy the three Saro Princess flying boats that were stored at Calshot, but no agreement was ever made and instead they bought the Short Solent, five in all. Besides the three you mention they had G-ANAJ "City of Funchal" and G-AKNU, the latter crashing in 1957 with the loss of 35 lives.
On 30.9.58 Aquila decided to close down as a flying boat operation was no longer viable with the increase in Mediterranean tourism which then commonly used DC6, DC4, Viking, Dakota, Hermes and even Viscount aircraft.
The three Solents were towed to the Tagus estuary near Lisboa where they lay for 13 years. By the end they were decaying and had to be broken up. They were towed there as it was thought a new airline may operate these three birds, but that was never to be.
Between 1948 and 1958 Aquila had 13 Sunderlands, 1 Sandringham and 5 Solents.