Defined benefit pots are generally best left alone and I would expect both of them are DBs, being EY as well as Aviva.
I was in my first job for 15mths, mid-eighties, had to leave a tiny amount in the pension (related to contracted out I think) - it has been growing at 9%/annum, and although it will only be a small pension per year, it will be good compared to what I Ieft in!
Second employment, there 5.5yrs, again the predicted pension has grown at a good rate and will pay out at 60, as that was the womens retirement age when I joined the scheme. Again, it will be a reasonable annual pension compared to what I was paid in the employment, even better if I leave it another couple of years after 60.
Am not sure why special said anything you put in now will lose value - it could do, most funds go down as well as up, but if you drip feed money in monthly from now on, you will smooth out the peaks and troughs. So some monthly payments may lose, but others will gain. Over the amount of years you have, they should more than even out and hopefully grow overall.
We have been investing in both stocks and shares ISAs and SIPPs for almost 20yrs, whilst one fund is down overall, that is only because I invested a lump sum in my naivety many years ago - we learnt our lesson and everything is now drip fed. Generally we have had growth, in some cases spectacular, in other cases not.