Any decent tyre place should be able to do that, usually costs me under £10. I wouldn't knowingly drive with a screw or nail in a tyre when a proper repair is so cheap.
I recently fitted a full set of bearmach poly bushes and i'm happy with them. 3yr/60,000 mile warranty as well, which is longer than superpro. got them from here http://www.mailorder4x4.com/acatalog/Defender_Bearmach_Poly_bush_Kits.html
You can still usually get them from a motor factors or online cheaper then you can with a halfrauds trade card though. Also if you look at the specs halfords own brand batteries are lower CCA and AH than other make equivilent models.
Personally I'd go for something like http://www.tayna.co.uk/019-Numax-Car-Battery-P1725.html 100AH 850CCA and £88 delivered.
spending money on a td really isn't worth it the 200tdi is far superior. from a conversion point a defender 200tdi is easier to fit that a discovery 200tdi. If i was looking to covert a td now though I'd go for a 300tdi.
As a budget damper I'd recomend Armstrong. I fitted them to my last rrc when i redid the suspension and fitted 130 spec ones to my current 110 last year. The ones on my 110 are a bit harsh when its empty, but loaded up it rides well.
All mine needed was a new set of pushrods, a new belt and tensioner (and a replacement injector pump as thats what caused the belt to go). I swapped the head at the same time, but that was a job on the to do list anyway.
It largely depends on the driver, an aggressive tyre provides more grip and driven sensibly will do less damage. However if the more aggresive tyres do spin they'll do alot more damage.
last year when laning with a friend i could crawl up a wet grassy lane without spinning yet he needed a run up and actually stopped halfway up with no grip. I pulled him the rest of the way without spinning.
My tyres are michelin XZL though not simex copies.
Its superwinch part number 6459, not sure if its still available. If you pm me your email address I can send you the manual with the parts diagram/part numbers in.
Martin
It does sound like there is something wring with either your engine or how its fitted. It shouldn't vibrate at idle any more than the 2.5NA did and shouldn't be much louder.