So quick update on this.
I had been umming and arring about what kit to go for and looking on eBay and gumtree etc. Ending up with the more expensive option ad buying some JL audio gear off a lad in Oxford.
JL Audio CP212-W0v3
JL Audio JX1000/1D
JL audio is great gear and this bundle had the larger 1000d amp included.
In Hindsight this set-up is complete overkill, after setting up the amp to its optimum settings the bass was ridiculous. So now have it running at about quarter power, 80hz and no bass boost and its sounds great - I just think I should of bought the single sub and the smaller amp! Although surely this now presents and opportunity to upgrade the headhunt and internal speakers?
I must say though that even with the bass at its initial settings the S8 is extremely well put together any rice car would have virtually self imploded, but the old girl barely shook.
Pictures attached