I am sorry to say that your idea will not work, but trust me: I know a LOT about sports betting. Really really a lot.
The system you want to make is NOT going to work. I personally tried that a few years back when I was still very naive about sport bettings together with someone from the UK, and we ran really large capitals. We played around with tens of thousands of dollars.
It was actually very easy to find the arbitrages. We had all the scripts for that, and beside that we have combined the information with some very sophisticated horse racing software (which for we also paid quite a large amount of money), so we try to focus the bankroll to the most possible loosers. And it worked perfectly: we found the arbitrages easily, and we picked up loosers too enough to make us a profit (because our goal was to find a horse which is unlikely to win, doesn't have very high odd, because obviously you need huge capital to lay a bet on betfair with an odds of 40, and also picking up loosers was a ticket for us not to be banned by the sports betting sites - at least so we thought).
And then:
BOOM. Trying to place a 1.000 USD bet and the ladbroke gives an error message: the maximum amount you can bet on this event is 0.56 USD (no joke). And then sports betting sites, one after each other limited our accounts (and we had accounts with almost every one of them). No worries, we told, as we have organized ourselves and played from multiple accounts. But it didn't mattered: they just got limited to such a ridiculously small amounts, that it wasn't worth at all. All these, while we actually lost thousands of dollars at the sports bettings sites, money we have earned back on Betfair of course.
We also combined this with an affiliate system so a share of the lost money was returned to us from the sport betting sites. That was the major source of income from this activity of course (as the arbitrages are not so high that you can make really much money).
Drawing the line, we have made some money. But to tell the truth I would have been making more money sitting at my laptop and writing a program as with this one, and with a lot less stress.
As I told: this was 2-3 years ago or so, don't really remember. Since then, they have better protection systems, arbitrages are harder to find also, because sports betting sites react a lot faster to market changes. Market does change fast, arbitrages are difficult to make (remember you need to make sure that the sports betting site does accept your bet, before you can lay on Betfair, and that sometimes take 10-15 seconds, and in this time markets can easily shift significantly, etc.). Plus you will have all the stress, that "wow, this works", and then your next bet will be limited to 0.56 USD, or you account locked, etc., etc.
With sports bettings there are ONLY two ways of winning, no more:
1. Guessing the results
2. Making (high frequency automated) trading on Betfair (or similar)
In BOTH cases you need something like this:
https://bitcoinstarter.com/projects/1000 (please take your time AND read it carefully). Essentially it's about identifying the events where the market has a wrong prediction. In most cases (because in sports are surprises too of course), the market will correct itself and then you're in money if knew that ahead. It's about eliminating the subjectivity of the market and rely your decisions on lots of facts, analysis, cross-analysis, etc.
The project I have mentioned is the first step of a bigger plan I have. At the described stage it will help bettors to place more educated bets and actually turn the advantage to their side. Once this project is completed, up and running, it will also serve as a base for step 2: developing totally automated high frequency trading robots for Betfair.
