Stick with the SSIA!
In your situation I would lower my pension contributions in favour of the SSIA. When the SSIA matures - you can always contribute some of it as a lump sum AVC to your pension.
Lump sum pension contributions attract tax relief as normal, provided your total contributions are below the
generous annual Revenue limits. The limits are set at a % of your income in year of contribution (at your age 20%, rising to 30% as you approach retirement). You can always trickle the SSIA lump sum into your pension gradually to ensure you remain under the annual limit.
Note that if you draw income from your pension when you retire (via an annuity) you will be assessed for income tax on that income. This reduces the present value of the tax relief considerably. So even ignoring the ability to benefit on the double (as suggested above), pension contributions are not much more attractive than the SSIA. And as blank points out, the SSIA is more liquid.
This assumes you are "good with money".
If you think you will "splurge" the SSIA lump sum on something silly, then stick with the pension now.
Postscript: it also assumes that by lowering your contributions, you will not lose any employer contributions. In some occupational schemes, employers will match your contributions. If paying into your SSIA meant forfeiting your employer pension contributions, I would probably stick with the pension after all!