Thanks for everyone taking the time to advise,
Still investigating but AA does look like the way to go.
I don't mind the upfront cost, to a point. I like to keep the monthly within reason.
What got me looking a little harder into bonding was as well as general overall improvement was my daughter often works from home at our house and really struggles with speed.
I imagine could be a multitude of reasons but her VPN (cisco anyconnect) slows to a crawl on my internet.
any other PC = 70 down & 11 Up. VPN using any online speedtest & confirmed by just general slow file download,lucky to get 5 down & 2 up -usually worse & have had 0.3 upload.
Her company & Zen (FritzBox) both say nothing to do with them but no way of finding out really but do read Anyconnect is pretty bad on speeds.
It is much better at boyfriends on Virgin (not 100% sure which one but I guess minimum 150mbps).
Perhaps more VPN friendly modem or just raw speed enough to overcome.
I don't expect anyone to advise on what to do about the VPN but just mention. Also someone advised load balancing & perhaps it would help a bit but think/hope bonding would give the best chance. When speeds were bad we made a point of not using anything else that might effect bandwidth.
Thanks again.