Scrambler 2006 Scrambler Rear Suspension

I have owned my 2006 Scrambler from new, and have been very happy with it. It has the standard rear shock absorbers and springs, which have worked perfectly well for the past 13 years (it has road tyres).
Last week during a biking weekend to Scarborough with a couple of pals we took some trips across the N Yorkshire moors on quite rough tracks. For the first time in 13 years the rear suspension felt inadequate as I tried to keep up with a pal's new Africa Twin (hardly a fair comparison, I hear you say). It was fine up to 50 MPH, but the rear wheel started skipping above that as the shock absorbers just could not react quickly enough. My question is: if I did upgrade the rear suspension then what would it be worth changing to? Bearing in mind the value of the bike now, I hope no one suggests spending £1200 on Ohlins units (that would be absurd), but would some of the other types I've seen advertised in the £100-£200 range give a worthwhile improvement?

Such as:

https://www.ebay.co.uk/itm/Shock-Ab...ambler&hash=item5b58d2a17f:g:33YAAOSwiSZdMUAB

or:

https://www.ebay.co.uk/itm/Pair-Sho...007/372769608633?_trksid=p2485497.m4902.l9144

Any comments would be appreciated.
Alan

 

I found these Hagon rear units recommended on an American forum, they would seem to be well thought of for just over £200/pair:

http://www.hagon-shocks.co.uk/catalog/partdetail.aspx?PartNo=36009TTSA