Interesting point, EmilGil. I did get this advice from Tom A about the film:
Try the HP 617 with a lower contrast developer like Kodak's D96. It would work well in your bright sunshine now when summer comes around.
Check the expiry date on the film, it is not critcial, but if it is more than 10 years out of date, get some Benzotriazole to cut the fog. I usually mix 2 grams of Benzo to 200 ml of hot water and I use 10 ml of that for 1000 ml of developer. With the D96 you can add it to the stock. If you keep adding it to the reuseable developer you end up with too much and it slows the speed of the film.
Unfortunately there is no dating on the film packaging. I'll just experiment and see what I get!