My advice would be leave it there , i actually counted the other day how many books i had money in and it was around 35 , you could probably argue that you need all your float but 50 here and there won't do you any harm .
I would hazard a guess the reason you missed the arb is due to the delay in having to deposit , don't play blackjack ( because sod's law will mean you'll probably end up losing half of it ) or take a loss , jot it down on a bit of paper " i've 50 quid in jaxxs as time passes you will arb there again and won't have to deposit .
found a 60p loss on a £50 jaxx arb this morning but couldn't get a bet on. kept click submit bet in the bet slip and it would load for ages and then nothing would happen, no message, nothing. tried it in firefox and ie and same thing. pissed me right off!