Running a disc mower on mf 200 series

Maybe not when tractor is fitted with a spool. But tipping pipe can work independently of arms if connected to EXT2 on the 3 way valve. You most likely have your spools connected to EXT2 though which is why yours cannot. (or an aux pump and no 3 way?)

There are a few options for @massey 265:

1. If you have a 3 way valve use EXT2, if you don't already have the valve fit one they are cheap and bolt on with 2 bolts. If your tractor has pressure control on quadrant then even better as you can leave in constant pumping and use pressure control to control height of mower.
2. Fit a spool (you will still need the 3 way valve), it just plumbs to EXT2 on 3 way and returns through a port on left-hand side if top cover. It's relatively easy to plumb but a bit fiddly with hoses and mounting.
3. Fit an aftermarket 100 series spool, simple 2 bolts no plumbing except screwing in the two remote hoses, it replaces the 3 way valve or cover plate. This option may depend on if your cab has a floor over top cover or not. Spool levers end up between your legs which is fine to use but reduce space getting in and out of seat. I have one fitted to my 135 but just screw levers off when not in use and it works well.
4. Just buy a drum mower that swings out behind when in transport position.

you can see mine here with th levers removed.

Link: https://tractorpartsireland.ie/product/selector-valve-with-spool-valve-monoblock?gad_source=1&gclid=CjwKCAjw65-zBhBkEiwAjrqRMFQZpJTN1ieKEQN44NrwkR9_5UbNEBfRIzXsP3lAg97Kp77EoQh6ahoC9H4QAvD_BwE One lever selects Linkage / single acting or double acting, the other is a single spool.

Edit:

This one is interesting: https://www.bradleytractorparts.ie/product/diverter-valve-kit7?gad_source=1&gclid=CjwKCAjw65-zBhBkEiwAjrqRMPWHfCnWk-0cbdxeEZtPbQA1MxMjfyHhDcXGzq3KptUxC0ZP45tOMhoCKr0QAvD_BwE as it lets you work arms and a single spool independently, although the arms are controlled via the extra lever and not the quadrant. It's also a complete kit with all hoses bots etc (This can also be achieved with option 2 above, with a spare spool and some extra plumbing )

Also might need a Cat II version, but would really work well with this https://www.bradleytractorparts.ie/product/diverter-valve-kit7?gad_source=1&gclid=CjwKCAjw65-zBhBkEiwAjrqRMPWHfCnWk-0cbdxeEZtPbQA1MxMjfyHhDcXGzq3KptUxC0ZP45tOMhoCKr0QAvD_BwE as the one disadvantage to working the arms from a spool instead of the quadrant is the ability to consistently set working height.

fair price difference between the potttinger and the bellon. Anyone have any experience with the bellon? What would they be like?

ya they are a Vicon. Great mowers too.

I've a Malone ProCut 800, I'm happy with mine, it's a heavy machine, you'd know it hanging off the side of a 390 but there are a few posters here not happy with them getting wrapped up in heavy crops. I wouldn't be as big a user of fertilizer as many of them though. I'd say it's definitly superior to some of the cheaper Italian built mowers.