Topper, flail mower for MF 135

Hi Guys,

So a bit of advise please. About 14 acres here are varying in degree from fair to poor land from bad drainage and rushes. This autumn I'm hoping to get a digger in to clear and make more drains to the soil improves and so it can all be travelled by tractor and grazed for more than 2 months of the year.
I only have a MF 135 and a finger bar mower and 4'6" drum mower for cutting hay. The old hay meadows are gone wild so last week I cut them with the disc mower and collected all the grass and rushes by cock lifter...hard work. The other 2 fields I let the cattle in but I only now discovered that younger cattle (only 18 months old) dont seem to like taller grass like the cull the cull cows that used to be here for the last few years. This meant another 2 fields with a heavy swarth that would need to be collected again....no chance so I borrowed a neighbours 6ft topper and topped them, the 135 was just about to handle it in 2L.

Question, moving forward the remaining maybe 6 acres are worse again and there is no way the 135 would run a 6ft topper on them. I dont like borrowing machinery as I'm always afraid that I will break something on someone else and would prefer my own. Seeing as this cleanup project will probably take another couple of years whats the best machine to purchase. As i see it i can do the following:

1. After the digger has been in get someone with a mulcher in to cut the worst 6 acres (rushes would be above my waist in this area and wont have been cut in 20 years. Then purchase a 5ft topper to maintain it. Problem is I have heard horror stories of breaking shear bolts every 30 minutes etc etc. If this is the best solution what topper is best? My view on the topper is that it will also do all the "good" fields fairly handy. Are some makes better than others?

2. Buy a compact flail mower like this https://www.compact-tractor-ireland.eu/product-detail/heavy-duty-flail-mower-5ft-katana-machinery/
and do all myself and it will let me maintain it. What are these like, has anyone got one? Can it be used as a topper on regular pasture? Is it slow if using as a regular topper? (I know it will be slow work on the heavy rushes)
If this did both jobs at a decent pace then i dont mind investing in it and i will be finished

Your advise would be appreciated