I assume the other houses on your estate/road were also built at the same time and by same developer?
If so they will probably have the same restrictive convenant in their title.
Now it will all come down to the wording of the restrictive covenant.
Because it may be that the beneficiary of that covenant isn't just the original developer but also all the other residents on this estate/road. In which case your neighbours could enforce this and no motor home/caravan can then be parked there.
I can't obviously read the covenant and I have no idea if you are freehold or leasehold either (which will matter to an extent).
It may also be that the land your estate was built on was part of one parcel of land and that there is a Head Freehold.
I own a Head Freehold where I can enforce restrictive covenants on 10 other households. Mine include prohibitions on building any additional detached buildings, altering roof lines, keeping roof tiles in particular banded colours etc but also I could be forced to let my neighbours sheep graze in a specified part of my garden every May (yes really!)
Our house is over 200 years olds and the neighbouring houses are a mix of Victorian and Edwardian. I was advised when we bought that most of the 76 Restrictive covenants were still enforceable including the sheep grazing.
So what I am saying is that however ridiculous it may seem, it may still be valid.
I don't know how many houses are on your estate but if you are all in agreement you can have a restrictive covenant dispensed with if you are all equally able to enforce it. However where there is a head freehold situation it's much tricker.
Not much help I'm sorry.
You need to ask your solicitor who the beneficiary of the covenant is. And is there a Head Freehold as beneficiary?
If the beneficiaries are your neighbours. Don't immediately rush around asking them if they wou,d be willing to ditch the covenant. Even if they are it still has to go to Land Tribunal which is a lengthy process.
Again sorry it won't help if your sale but if you're fully informed at least you know where you stand..