Originally Posted by
chrismoose
would it be possible to buy two round-trips, one uk-AMS, the other AMS-elsewhere (both sets would be KLM)?
Of course it is. What's to stop you?
Originally Posted by
chrismoose
Following on from that (and this may be the sticking point) could I combine the two sets in one direction (allowing the AMS minimum connection time), or would this mean I'd have to collect luggage in AMS and re-checkin?
You would have to AT THE VERY LEAST observe the minimum connection time, but NOT FACTORING IN ADDITIONAL TIME for potential delays is just asking for trouble. You can ask to have bags checked through, but the agent will be well within their rights to refuse if the connection no longer looks viable due to whatever circumstances are in play on the day in question - so you really should be factoring in as if you have to wait for, collect, and re-check your bags in Amsterdam. Plan pessimistically.
Remember that long-haul flights (in particular) can often experience considerable delays. If you're travelling in winter, you may have sudden, short-notice weather-related cancellations on the shorthaul network to contend with. And if you are booking many, many months in advance, you may find that some, or all, of your flights get retimed and you suddenly no longer have a valid or realistic connection.
When booking travel on separate tickets, remember that you are assuming all the risk for missed connections, so you MUST build in sufficient time - and then add an extra couple of hours of buffer time - to increase your chances of actually making the connection, and of having the agent agree to transfer your bags
If you want to spend a few nights in Amsterdam, why not have nights there in
both directions?