Hi Galway Girl,
You are in a pretty good position - site purchased and house to roof level with no debt. Well done! Many banks can fund the balance for you. I assume your husband is an engineer? with professional indemnity insurance? if so, all your husband has to do is to confirm to the bank the cost of work completed to date, and confirm costs to complete.
I would agree with your view of ulster bank. They have reasonably good rates, but tend to be a bit sticky with cheque issue. I would be thinking more about IIB, Bank of Ireland, PTSB, etc who's customer service in my experience is better. As you say, you can look at rates and best value on completion of the property. Many banks now offer free switchers at very good interest rates. In terms of costs I generally advise customers to allow c€2,500 for legals. you will need mortgage protection insurance (see links for best value) and the mortgage broker (if you choose to go that rouote) gets paid by the bank (generally 1%)
As a general rule a decent broker can arrange approval in about 5 working days or better (if you have all documents to hand) and then its over to your solicitor to do the legal work and requistion funds from the bank. In my experience, from the time you sign up with your solicitor, to the time he/she recieves the cheque from the bank, on average takes 2ish weeks. (average - fair degree of variation also)
Does this help?