Yes, I get CB and my gross income is much higher than £50K. By my reckoning, you are in a perfect spot: your gross income is £54000 a year. DB pension contribution brings it down to £51300. If you now contribute £1301 to an AVC, your income will drop below £50,000. However, it will only cost you £780 (or £65 a month!) because of tax relief. You'll then get about £120/month for CB. Hence, save £65 a month from your net salary in your pension; Her Majesty will then top that up by £43 and, furthermore, give you £120 now in CB! In other words, there's £163/month sitting on the table that you have been ignoring. Apply for CB now and get back 3 months CB retroactively. Make the AVC payments before April 2017.
OK, now, what about ER? If you work until aged 45 at the same income, then your pension eligibility at aged 60 would be £14910/year. (Note: everything I estimate is in today's £; your pension is probably index-linked, as is NI, so we can ignore inflation). Your national insurance at aged 66 would be £4902/year. If you want to retire at age 45 with an income of £2000/month, you'll need a savings pot to tie you over until the pensions kick in (you'll also need some savings to make up the shortfall in your pensions when they do kick in..). Using CFireSim, I calculate that you will need to have £450,000 outside of your pension to yield an income of £2000/month (in todays £) when you retire at age 45. You have 12 years to save this up! That's £2012/month assuming you invest your monthly savings in something that yields 7% return above inflation (i.e., something like a 80% stocks/20% gilts allocation). The big problem is that you need to save this outside of a pension (hence, no tax relief) otherwise you would not be able to access it before aged 55. Qualifying my earlier statement, this money should go into an ISA.
So, I'd ask the following questions:
1. How much could your husband contribute to this savings plan?
2. Do you really need £2000/month when you retire at aged 45? You will have teenagers at home, but will your husband continue his part-time work?
If you are willing to retire at age 55, it gets A LOT easier: first, all the of the savings you'll need can go into an AVC pension and receive tax relief. Your workplace pension (if everything continues as it currently is...) will give you an income of £21000/year at age 60, NI would give you £7369/year at age 66. For an income of £2000/month, you will need £250,000 in savings at age 55. For this, you'll need to save about £410/month from now on. However, this can go into your AVC pension and, consequently, will cost you only £246/month from your net income given your tax bracket. The one snag is that not all of the £250,000 will be tax free when you withdraw it; only about £168000 will be. However, if you put the rest in drawdown scheme, then your tax rate will be at your marginal rate of 20% as you take it out.
Age 55 seems like an eternity away, but it will come sooner than you know it. You'll be shocked.
My biggest piece of advice if you want to retire early is that you do everything you can to keep that marriage together! With two small children and a demanding career, it's very easy for the marriage to get stale and for resentment to build up. Don't let that happen! Spend time alone together and keep dating each other. Make sure you share with each other your goals and expectations. By all means, move closer to your family if you can. You need the support. Good Luck!