Hi Glen, I'll do my best, here goes,
1)Most of the timber length was actually rotten so used an old chisel to scrape and dig it out, time consuming but best to remove all the bad wood.
2)There were two plates, the one you can see and one a bit further up, I dont really know what there purpose were, but sort of gathered they are there for a reason so put them back, I can only surmise at this and guess it may be something to do with the polystyrene, giving it a bit of extra support.Sorry I cant be more specific but someone might come to our rescue!!
3)1995 Abbey Stafford (now swift I believe)
Hope this helps
Kev