Worth mentioning that a glass panel might be mandatory to sell planes these days but it adds nothing to mission capability, and probably doesn't help with pilot workload either.
The G1000 is basically a GNS530 with engine instruments added.
It won't give you enroute weather (no service in Europe), won't give you a lot of useful traffic (few people fly with transponders, currently, and there no Mode S traffic uplink in Europe). Terrain is useful but this is normally taken care of during planning.
It also concentrates failures and expenditure into one item which, when it goes, is going to set you back massively, lending a whole new meaning to "partial panel"
Prop de-ice is very effective and far cheaper than full de-ice of any kind.
The other thing is that the only way to get a glass panel, generally, is to buy something new. GBP 150k would get you a new C172 whose IFR mission capability is close to useless. A good used TB20 will cost less and will do
far more.
One can do it for less - plenty of 30 year old planes around with the equipment - but then one is very likely looking at knackered avionics and this tends to cost a lot of money. That's why I believe buying something really old just means you spend the money over the next few years.