1. Assuming your old radiator was an 800 x 600 double with single convector fins (T21) it would have had a heat output of around 1.1 kW.
2. The new one has a specified heat output of around 1.7 kW.
3. Even allowing for the different heat patterns of a vertical V a standard radiator, I would expect it to be no worse than, and probably slightly better than, the old one in terms of room heating.
OK That sounds good then Thank you.