One thing I will say is don't buy one of the cheap things you see on some of the well known auction sites or from the jungle river.
I have some old (30+ years) SIP Migmates that I love and use regularly BUT I have modified them and they are not very original any more but even in their unaldulterated state, they were better than the cheap stuff that is basically dumped on us by China (they're probably better than the latest stuff from SIP as well )
It's like welding rods, buy good ones and you will realise how sh*t the cheap no brand/label dipped in sewage and dried ones are.
TBH, I'd say the Clarke model you have is a good welder for what you are aiming for but I'm not a professional welder and I don't spend my life using welders so my recommendations are pretty worthless really. Have a good listen to what the other chaps say on the forum, somebody who's got much more experience than me will point you in the right direction.