Administration needs

I am just dipping a toe in the water as the start of planning for AE. Our start date is Jan 2017. Small employer, catering trade, most of our seven employees are on a bit above minimum wage but part time. I have three who could be in the band where automatic enrolment is required. One of these, our key staff member, is adamant she will leave if we start taking deductions!
Reading up, the pensions regulator mentions a lot about payroll software (here we go, another unnecessary expense) which we don't use. We employ hmrc's RTI and record it all on excellent spreadsheets. What exactly will I need to have to comply? Is it necessary to buy expensive software?
As a good employer, I want to give my staff the best possible return on investment but sorting out the best scheme is a nightmare with all fees and charges. I have looked at NEST but note many comments say it's rubbish and not cheapest on charges. Clearly it's performance that counts at the end of the day but is this in any way predictable?
I probably shouldn't say this here but I have a phobic distrust of IFA'S (having been robbed by a few, big fat fees, under performing funds, take the money and run...you get the drift!) so do not desire to employ one to advise on this. I'd rather put such money to grow in the employees pension. Is there any IFA'S that get paid on results?
Can any employers who have come out of the other side of this nightmare already offer guidance as to what have been good decisions?
All advice gratefully received.
Peter