I would:
Max out all four S&S ISAs (You and Mrs, this tax year and in April).
Split taxable accounts between you to take advantage of the 2x £5k dividend allowance.
Have a look at where the capital gains are for each of you around March and what Capital Gains Allowance you each have left. Then figure out how to legally harvest enough gains to keep you under the threshold (sell and spouse buys, sell and buy in next years' ISA, sell and buy something slightly different).
This would shelter the growth but you'd be putting after tax income in.
If Mrs Uksaver will get salary sacrifice on pension contributions (so saving NI contributions on AVCs or whatever), then this is a good shout. If she will have annual tax free allowance left after receiving her DB pension (I think unlikely after 20 years), then also a good shout. If it is just the difference between paying 20% tax now and (20%*.75 + 0%*.25)*(changes in tax policy) as it would be in her SIPP it is probably a wash.
VCTs would be the next logical step, but sounds like they're not for you.
Any Share Save schemes or stock options available to you?