Phester,
Your probationary period could be the stumbling block here. If you have moved to a more senior position in a similar field then your broker should be able to argue your case on this and have this condition waived.
As regards the mortgage amount there are a few ways around this if you are happy to go for a different repayment method?
1) Ask broker to resubmit to Ulster Bank but under a 5 year fixed rate. You will easily get what you qualified for previously (and a lot more if you like).
2) Submit to IIB under a 3 year fixed or capped tracker mortgage (if your broker has an agency with IIB, if not just change broker). Again they will allow a bigger mortgage.
3) Submit to First Active under a 5 year fixed rate (if your broker has an agency with First Active, if not just change broker). Again they will allow a bigger mortgage.
First Active 5 year fixed is best in market at 4.89%
Don't let your broker bully you, find a reputable broker who is independent and has agencies with all the lenders.