Another newbie so cannot offer much of an opinion (!) on the petrol turbo model but do remember these are expensive to run cars whatever engine. If you spend a bit of time on this site most of the issues will be evident and you need to assess the car in light of these.
'Full dealer service history' (plus all MoT documentation) would be good – I suspect the FSH will include several visits to a non franchised works for a 'oil and filter change' service. The 18,000 mile service interval is rare in cars and it comes with a cost in terms of the work and inspection schedule being far more than these simple items.
'Great condition' well the outside is mostly composite and aluminium panels so easy to make look good – it's what can happen underneath you need to check.
'60,000' miles in a +12 year old car is possible but the first 30,000 are likely to have been as a rep-mobile 3 year stint so what's being going on since? Even then age before miles to price a car once out of warranty.
What specification? If cloth, Expression with no toys start much lower (but with fewer problems in the future) otherwise I suspect the few regulars left here would be offering £600 as long as it had a 12 month MOT, £200 otherwise.
I believe the 2.0T would use the PK6 gearbox so watch out for test drives with the car warm (2-3 and/or 3-4 changes are a problem cold), usual wet car looks and HPI issues.
Get a good one and care for it might give you some very cheap comfortable motoring but these cars are not simple and there has been a steep learning curve so the later model the better (54 most desirable).
The only real advice I can give otherwise is do not switch to the Laguna as your will pay more for less and still get all the same problems as they share the running gear.