By 2000, this parliament of the British Empire has 325 seats, with the following composition:
Great Britain - 125
India - 65
Canada - 23
Australia - 20
South Africa - 20
Malaya - 17
Nigeria - 12
East Africa - 10
New Zealand - 10
Ireland - 10
Rhodesia - 8
West Indies - 5
Taking into account the populations other than Great Britain (and presumably Ireland with it? Why would Ireland have separate representation if the POD is before WWI?) and India on account of their "influence", the rest of your seats are skewed.
These are approximately the current population figures:
Nigeria - 154 m
East Africa - 115 m (combined Kenya, Uganda and Tanzania)
South Africa - 50m
Canada - 34m
Malaysia - 28m (Peninsular Malaysia or Malaya - 21m)
Australia - 22m (about 29m with PNG)
Zimbabwe - 12m
West Indies - 6-7m
New Zealand - 4m (even with Fiji it would just barely break the 5m mark)
Those kind of figures for the seats may work in say 1920-1940, but once suffrage began to be extended to more of the populations in the various colonies after WWI and especially after WWII (and you still have WWII occurring in your post) then such figures are never going to fly over the long term. Certainly not approximately 60 years after WWII. As octaviuz's post mentioned, eventually the parliament will evolve to expand the franchise along with the education of the colonial populace and the British and old dominions so that the former know their rights and the latter don't cower in fear at being ruled from Bombay.
By 2000 I would expect (if the imperial federation didn't split before then over the issue of representation) that the lower house would have the following seats (approximately):
India - a third to a half of all seats
Nigeria - 125 seats
East Africa - 125 seats
UK - 125 seats
South Africa - 95 seats
Canada - 70 seats
Australia (with PNG) - 65 seats
Malaysia - 60 seats
Zimbabwe - 25 seats
West Indies - 10 seats
New Zealand (with Fiji) - 7 seats
Ireland - 7 seats
Now with 589 seats (and excluding India's 295 or 589 seats) some folks will say this lower house of parliament would be far too large, but then a lower house of parliament of between 884 to 1,178 seats isn't all that large considering that population of the areas represented would amount to over 2 billion people. Consider the following countries/international organizations and the size of their legislatures:
China - 1 billion people and a lower house of 2,987 (of course China being a one party dictatorship means parliament size doesn't have quite the same relevance)
India - 1 billion people; lower house of 552 and upper house of 250 (combined 802)
European Union - 500 million people; lower house of 736 and "upper house" of 27 (combined 763)
UK - 61 million; lower house of 646 and upper house of 707 (combined 1,353)
France - 65 million people; lower house of 577 and upper house of 321 (combined 898)
With between 23-30% of the seats in the legislature anyway, it's unlikely that Britain, Ireland, Australia, Canada and New Zealand are going to be (frequently) overwhelmed on certain key issues which would be designed to require a certain majority in order to be passed. Nor would India completely dominate since with only half the seats any measure that is favoured by
all of the hundreds of Indian representatives (unlikely to start with, especially once party politics comes into the picture) would also need some representatives from elsewhere to be passed.