Thanks mate, the build isn't going too bad, if a little higgledy piggledy at the mo.
Gaskets, well last time when I did the 200tdi I used Turner engineering for the bottom end set as they could supply a victor reinz set, everywhere else I could only find the almakes/britpart/bearmach standard sets, and from my experience of them, they aren't great, very thin, paper thin compared to the victor reinz ones.
The top end I bought an elring set, which I think I sourced via lr direct.
Now this one, the 300tdi, I again sourced via lr direct, by part number and was able to get payen and elring gasket sets, both good quality and very happy with them.
So I'm not really sure which brands are available when it comes to the td5, although my brothers td5 needs a head gasket and was looking at gasket sets the other day. Turners don't say which brand theirs are, and via the usual parts places I can only find britpart, (in a set that is) Maybe Turners are just supplying britpart sets, who knows.
Probably doesn't help you, and have been wondering what to do myself.