I believe that Go-Ahead, along with almost all bus companies, has a clause about paying back training costs if you leave within x amount of time - but I can't say how much, or what timescale, or if there's a sliding scale. They ought to tell you this as part of the job offer / before you sign a contract. The job offer ought also tell you what pay rate and hours a week they are offering. (Having said that, if you've got a job offer, and things aren't clear, it's not unreasonable to ask questions before you accept. It's not a case of negotiating / haggling, though, as it's a collective agreement.)
At most places, there's an hourly rate for trainees, then a rate for new drivers, then a scale that goes up a bit each year for a few years.
In terms of hours / pay, it's hard to say. Today's Go-Ahead London has been formed from several different former operations, including Metrobus (Orpington and Croydon), Docklands Buses (Silvertown), Blue Triangle (what's now River Road, Barking), First London (Northumberland Park), London General (South / South West London) and London Central (Camberwell, New Cross, Peckham) and Bexleybus (Bexleyheath.)
Historically, as separate employers, they all had their own pay rates, terms and conditions. I understand that some of the historic terms and conditions now only apply to staff who were there before they merged, but I believe there's still some variations.
Stagecoach is less complicated in this respect, although Lea Interchange, Walthamstow Avenue and Ash Grove were acquired from other companies so may be different to their other east London garages.
And some operators have ended up with separately negotiated pay / conditions deals at different garages.
Without knowing (for example) whether you're comparing GA Orpington with Stagecoach Bromley, or GA River Road with Stagecoach Barking, or what, it's hard to say. And I appreciate you may not want to go in to detail in public.
Another complication is whether there's a flat hourly rate, or whether there are enhanced rates for unsocial hours (very early mornings, late evenings, weekends) or for duties where the spreadover (total time from sign on to sign off) and / or time on duty (time actually worked) go over a certain threshold in a day. And whether breaks are paid, unpaid, or somewhere between the two (e.g. first 40 minutes of break is unpaid, any more is paid.) This makes it hard to translate the headline hourly rate in to what you can expect in an average week.
In practical terms, it's also worth thinking about how easy / time consuming it would be to get from your current home to the garage where the job is offered - bearing in mind you'll be doing this to get to early starts, get home after late finishes, and there will probably be some 'spreadover' duties where you have a few hours off (usually unpaid) in the middle of the day. And staff car parking is limited or not available at some garage locations.
Some operators have introduced remote sign on / sign off points, so you may start and finish a duty at different places, depending on whether you need to bring a bus from garage or back to garage - this can suit some people, but if you can and need to park your car at the garage, then it means the travel time between garage and the remote point ends up unpaid at one end of your duty.
Best of luck, whichever of these (or other) options you go for.
