Hi Richard and welcome to the forum
In my opinion, there is no problem with continuing to use e-bay, as I imagine the amounts you are talking about are relatively small.
A savings account is a good idea, as you will need to cover certain contingencies such as car maintenance, which tend to go out in big lumps a couple of times a year. So long as the balance remains below say £500 I would have thought your IP would be happy with this.
If you are lucky enough to have your parents-in-law give you a deposit for a property, then this is fine, so long as your new mortgage payments are no more than you are currently paying in rent. At the time that you both move into the property, it would be sensible to review your income and expenditure given that your girlfriend will now be contributing to the shared bills.
Pay rises will be regularly reviewed by your IP, in the context of an overall annual review. Generally, modest pay rises tend to be absorbed by usual cost of living increases, but each case is judged on its own merits.
As I am just one of the several forum experts, perhaps others may have a different view - and of course your own IP's opinion and decisions are those which are most important.
Good luck with your proposal.
Regards, Melanie Giles, Insolvency Practitioner for over 20 years.
For further details contact me at
http://www.melaniegiles.com and view my IVA blog at:
http://melaniegiles.blogs.iva.co.uk