Owning your own home

So the wife and I bought our one bed freehold house in Camberwell 2 years ago in May, absolutely love the house and the area, but now that we're both full time working from home it's become a bit of a squeeze. As some of you are aware we thought about selling up and heading off to west of Ireland (both Irish) where property is cheap and infrastructure is non existent. The more we looked into it, it just didn't make financial sense (3 years left on our fixed term we'd have to buy out of, salaries lower, tax higher) so we decided to explore outside the m25 in the UK (Banbury to be exact), but my car broke down on the way to a viewing and 5 hours in a layby outside Milton Keynes made me realise I don't want to live outside London unless it's Ireland.

Last night we looked at a 2 bed leasehold flat with twice the floor area as our house, advertised for 30k less than we'd hope to get for ours. What's the catch? The service charge is high (£2,600pa), and its in a transport link dead spot (relative to rest of london), not that it matters too much to us. Anyway we fell in love with it and want to make an offer.

Questions:

1. Are we insane to offer on the first place we've seen?
   
2. I've asked for details on breakdown of service charge, if its likely to change based on historical data, recent major work, projected major work, lease length - anything else to consider with leasehold property?
   
3. We're getting out place valued by the EA we bought it through later today, already have a purple bricks valuation and will get one from EA managing property we like too. Can we make an offer before we advertise our own or is that a black mark against us in the eyes of a vendor?