Honest opinion Phil - even based on 8 posts - the chances of you keeping the car stock are nil I reckon!
I think the reason why people will have 'fuller' values on here is you in many cases get an invaluable background to the car for at least the last persons owership.
Service history tells a lot but on here you also get a feel for how many issues they've had, accidents involved in, detailing pictures, parts used for spares and repairs, previous modifications..........its all definitely worth a few more quid than the guides (obviously all subject to someone actually posting up these things on the forum).
Generally forum members on here do tend to look after their cars better than the overage Joe as they're more of an 'enthusiast' than an 'owner'.........obviously there exceptions to the rule but there are a large quantity of OCD detailing nutters on here.
Keep looking though and with the plans you've got I reckon you'll get what you need - might need a bit of tidying but if your swapping the block out then its not that much bother.......even low milers have the niggling issues.