got one

hi guys i've finally got my hands on a disco again... 200 tdi mot till july, tax till may showing 155000 miles with reciepts for a new gearbox at 112000 and recon engine at 120000 she's on a H plate with the usual disco dents and scratches but drives mint. Did a straight swap for my 1998 td mondeo which i'd say was worth around £500 so bargain has been had me thinks. Its got a leaking front diff though are the seals easy to change? or can you recon a diff yourself as i've still got old axle from last disco i thought about recon that diff then straight swap over. if so what kind of cost would be expected on the recon job and would any specialist tools be needed? i'm a pretty confident mechanic. any advice appreciated guys. cheers