I need to replace one of my front tyres before SVA (2nd hand wheels).
I can get a new tyre of the same make size & model/tread pattern for a very cheap price.
The problem is the new tyre has an H speed rating, whereas the existing tyre on the other side is W rated.
Since both speed ratings are below the declared design speed of the the car, can anyone see this being a problem?

I assume you mean they are both rated OVER the stated max speed.

I would stick to the same rating. They wont like it. Blokey today checked all my tyre ratings even though they were all the same tyres.

Ok. Cheers chaps.
I thought that would be the case but the tyre was SOOO cheap!

I had different tyres at SVA. One was rated lower than the others. I used second hand wheels too. They were both above the quoted speed at SVA. It passed. I think he may have commented that one of the tyres was different but wasn't bothered by it.

do they check the tread depth? or only the speed rating?

mine are 2nd had wheels, right down to the markers on 3 out the 4 tyres, but i think they are from america and are still more than 1.6mm (only just!) not ideal, i know...

The only thing checked at SVA is the speed rating and as at MOT the speed rating MUST be the same on each axle.
Tyre tread is not checked at SVA.

sounds alright, mine ARE legal, but only just. could really do with not having the expense of new tyres before this car gets legal