RS Stock numbers for the Talema range 25 A / 40 A / 50 A:
https://uk.rs-online.com/web/p/current-transformers/7754909 or /7754903 or /7754912 Secondary 50 mA, good to 1.6 V. (Ignore ±400 A Output on the website, it’s wrong.)
https://uk.rs-online.com/web/p/current-transformers/1243897 50A:50mA (good to 1.6 V)
https://uk.rs-online.com/web/p/current-transformers/1243896 25A:50mA (good to 1.6 V)
What’s the p.f. of your heat pump when it’s pulling 5 kW (not Kw)? If it’s 0.87 or better, that’s under 25 A and so the 25 A c.t. will be OK. (Assuming it is 5 kW @ 230 V, if it’s spec’d at 240 V, so much the better.)