The data here is presented in 3 tabs, splitting out GB and NI. I'm not putting a border of any kind down the Irish Sea - it's just to make the data easier to view.
Current poll of polls data:
Conservative: 43
Labour: 29
Lib Dems: 15
BXP: 3
According to the Politax model this gives the Conservatives a majority of 107. I note that www.electoralcalculus.co.uk would return a majority of 104, but we are only talking about decimal places in terms of vote share so, prima facie, either model seems to be plausible.
Beware tweets and sites stating that the Brexit Party is ahead in various constituencies - they are almost certainly not. The forecast for the Brexit Party is still zero.
However, I would also caution against the theory that people voting for Brexit is splitting the Brexit vote in areas that might swing to the Conservatives. In strong Labour areas the Brexit Party standing is probably positive for the Conservatives. If the Brexit Party were not standing it is more likely that those votes, in Labour strongholds, would return to the Labour Party not vote Conservative. The Brexit Party standing reduces the Labour vote, leaving the objective of the Conservative Party of maintaining or improving their own.
For example, currently I have both Coventry North West and Coventry South as just about being taken by the Conservatives and people may argue that the Brexit Party could actually prevent that happening. However, the Conservatives' vote share is barely moving from 2017, the gain would be almost entirely down to Labour voters switching to the Brexit Party. Without the Brexit Party the Conservatives would be more likely to lose.
As ever, interested in any other thoughts.
I suspect you are right about Coventry South. I remember Tories were hopeful of winning that seat in 2017. In 2015 Labour won by about 3k votes while UKIP picked up over 5k votes. In 2017 Labour held the seat with an 8k majority over the Tories. It seems more UKIP voters went to Labour than to the Tories.
Many natural Labour voters may vote for the Brexit Party or abstain altogether but they won't vote for a Conservative. I don't think the Brexit Party will harm the Tories too much - whether it will enable them to win is another matter. I still think Labour will hang on.