OK, so I can get the Britpart kit for £53.50 or the mechanic has recommended OEM for £90 +VAT.
The link horse62 (thank you) is for £60+Delivery+vat.
I think that the engine is quite an important part of the Disco, so to be safe I might ditch the Britpart idea, sometimes you get what you pay for, and on this occasion I'm taking no chances.
I'm new to landys and I'd always thought Britpart was a good name.